Given an image how to identify whether it is RAW file or not











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I'm a much like beginner level, so pardon me if this is a very basic silly question. Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?










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  • Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
    – Chris H
    yesterday






  • 6




    To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
    – Joe
    yesterday










  • I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
    – osullic
    15 hours ago








  • 1




    It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
    – Michael C
    12 hours ago






  • 1




    JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
    – Michael C
    6 hours ago

















up vote
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favorite












I'm a much like beginner level, so pardon me if this is a very basic silly question. Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?










share|improve this question









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Temp O'rary is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
    – Chris H
    yesterday






  • 6




    To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
    – Joe
    yesterday










  • I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
    – osullic
    15 hours ago








  • 1




    It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
    – Michael C
    12 hours ago






  • 1




    JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
    – Michael C
    6 hours ago















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I'm a much like beginner level, so pardon me if this is a very basic silly question. Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?










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I'm a much like beginner level, so pardon me if this is a very basic silly question. Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?







raw photography-basics raw-vs-jpeg






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  • Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
    – Chris H
    yesterday






  • 6




    To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
    – Joe
    yesterday










  • I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
    – osullic
    15 hours ago








  • 1




    It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
    – Michael C
    12 hours ago






  • 1




    JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
    – Michael C
    6 hours ago




















  • Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
    – Chris H
    yesterday






  • 6




    To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
    – Joe
    yesterday










  • I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
    – osullic
    15 hours ago








  • 1




    It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
    – Michael C
    12 hours ago






  • 1




    JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
    – Michael C
    6 hours ago


















Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
– Chris H
yesterday




Relevant further reading: How to convert JPEG to RAW in Photoshop or similar?
– Chris H
yesterday




6




6




To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
– Joe
yesterday




To check - are you asking if 'given a jpeg, can we find out if it was once a raw file and then converted' or are you asking 'I believe that RAW is a type of jpeg and want to check if this jpeg is RAW'? (either are reasonable beginner questions, and both are easy to explain, but in different ways)
– Joe
yesterday












I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
– osullic
15 hours ago






I don't think it's a silly question, but I think it's the "wrong" question. Probably what you should be asking is, "what is a RAW file?"
– osullic
15 hours ago






1




1




It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
– Michael C
12 hours ago




It's been said here at Photo.SE many times before but it bears repeating: There's no such thing as a raw image. There is only raw data. Whatever you are viewing on the screen when you open a raw file is a conversion of that data. A light curve must be applied. Demosaicing must be applied to the monochromatic luminance values from each pixel well. Color balance, tint, contrast, etc. are all being applied to the image by the application with which you view it.
– Michael C
12 hours ago




1




1




JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
– Michael C
6 hours ago






JPEGs and PNGs have a single correct way to display them. They are already in RGB form and have a color space designated in their metadata. There is only a singular way to correctly display a JPEG or PNG. A raw file is not RGB, it is not gamma corrected, it has no color/white balance, no black points or white points set, etc. There are a near infinite number of ways a raw file can be interpreted. If one merely converts the linear luminance values of a raw image file to a raster format, one gets a blob of mostly black nothingness with splotches of dark gray here and there.
– Michael C
6 hours ago












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Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?




If you have a JPEG file, then it is not a RAW file.



RAW isn't a single format, but rather a collective name for image files that contain data straight from the sensor. RAW files need to be processed in order to convert them to more general-purpose image formats like JPEG or PNG. Most cameras can do that processing themselves, so that they save their images in JPEG format, or they can write the RAW data into a file for processing on your computer. Either way, if you know your file is a JPEG file, then by definition it is not a RAW file.






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    up vote
    22
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    Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc.), .nef (Nikon), .cr2 (Canon)...



    A JPEG file will always have the text JFIF somewhere near the start if opened in a text or hex editor, among the hieroglyphs (warning: if opening a non-text file in a text editor, NEVER save!). It is not impossible but extremely unlikely for a RAW file to have that.



    If you cannot see file name extensions in Microsoft Windows, uncheck "Folder Options"/"Hide extensions for known file types".






    share|improve this answer



















    • 5




      The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
      – xenoid
      yesterday








    • 3




      @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
      – Cornstalks
      yesterday










    • "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
      – rackandboneman
      yesterday








    • 1




      I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
      – xenoid
      yesterday






    • 6




      @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
      – Ilmari Karonen
      yesterday




















    up vote
    9
    down vote














    1. File ending: JPEGs end with .jpg or .jpeg, RAWs end with different strings (e.g. .cr2, .nef, .arw, ...)


    2. File headers: Usually, formats put some signature in there that tells programs.


    3. Size: Given the same size and motive, even quality 100 JPEGs will be significantly smaller. (e.g. 20 MiB vs 5 MiB)


    4. Ask a program that knows. Most (if not all) programs use the file header or other file-analyses to determine a file's format. IrfanView even tells you when you have a JPEG with a wrong ending (e.g. .png)





    There are more methods, but most involve some experience in this kind of stuff (e.g. a HEX-editor). If you want the answer to be low-level, then I would suggest to move it over to superuser.






    share|improve this answer



















    • 1




      At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
      – Tetsujin
      yesterday






    • 1




      @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
      – flolilolilo
      yesterday






    • 2




      I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
      – Tetsujin
      yesterday










    • @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
      – flolilolilo
      yesterday










    • @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
      – flolilolilo
      yesterday


















    up vote
    2
    down vote













    RAW format, as generally called, is a group of file types with different suffixes. There are *.raw files and proprietary files like *.cr2 for Canon, for example and many others. I am a Canoneer so the following is based on my experience with my Canon.



    Almost every manufacturer has their own RAW file format. Be also careful that some, Canon for sure, updates their RAW format so claim "All [Canon] image tools can open all [Canon] RAW images" is false. To preview a RAW file one need program that can process the the particular file format in particular version. Even mighty Photoshop have issues opening every RAW file.



    RAW file is a dump of the data collected from the sensor plus data containing the camera setups. It is complete and lossless acquisition of data from the camera to the memory. RAW format is not an image format at all.



    The cameras have built-in image processors (in case of Canon it is named DigicX) that interpret the RAW file to JPEG and show on screen and/or store to memory.



    When one use any digital camera the internal workflow is:




    1. Open the shutter (mechanical: slide first curtain away, digital: start saving the data stream from the chip)

    2. Acquire the scene

    3. Close the shutter (mechanical: slide second curtain over the chip, digital: stop saving the data stream)

    4. Dump the data acquired to the buffer

    5. Process the image to jpeg using pre-set options

    6. Show preview to the screen.

    7. Save the image

    8. Clear buffer memory.


    If the RAW mode is selected, the processor saves the data to image as-is in the body-specific format. If the RAW+JPEG mode is selected, processor saves the data as-is to image.cr2 (for Canons) and processed image to image.jpeg. If JPEG mode is selected only the processed image is saved and the raw data are lost forever.



    That's why the RAW images are humongous when compared to true image formats. If you have 12MPx camera with 16bit depth the RAW file holds 12 000 000 * 16 bits of image information plus negligible amount of data keeping the setups.



    JPEG is, on the other hand, file format dedicated to store images in files with reasonably size. It is based on lossy compression and benefits from the fact, that 50 shades of black are black to human eye, so why bother? It works similarly to .mp3 audio format - it ignores the nuances the detector can distinguish but human senses can't. The level of ignorance is regulated by the compression quality.



    How to identify RAW files?




    • They are humongous

    • Few previewers can process them

    • The file extension is not jpg or jpeg






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      Raw image files contain enough data to create a near infinite number of interpretations of that data that will fit in an 8-bit jpeg file.¹ Anytime you open a raw file and look at it on your screen, you are not viewing "THE raw file." You are viewing one among countless possible interpretations of the data in the raw file. The raw data itself contains a single (monochrome) brightness value measure by each pixel well. With Bayer masked camera sensors (the vast majority of color digital cameras use Bayer filters) each pixel well has a color filter in front of it that is either red, green, or blue. For a more complete discussion of how we get color information out of the single brightness values measured at each pixel well, please see RAW files store 3 colors per pixel, or only one?



      How the image you see on your monitor when you open a raw file will look is determined by how the application you used to open the file chose to interpret the raw data in the file to produce a viewable image. Each application has its own set of default parameters that determine how the raw data is processed. One of the most significant parameters is how the white balance that is used to convert the raw data is selected. Most applications have many different sets of parameters that can be selected by the user, who is then free to alter individual settings within the set of instructions used to initially interpret the data in the raw file.



      If you are viewing an image on a screen, you are not looking at a raw file. What you are seeing is one possible interpretation of the raw data collected by a camera sensor. That interpretation may be one of several things:




      • A jpeg produced by the camera using the raw data from the sensor and the camera's settings current at the time the image was captured.

      • A jpeg preview image attached to a raw image file. The jpeg preview is also produced by the camera's internal processor using the camera's settings current at the time the image was captured. It is attached to the raw image file. This preview is normally what one sees when looking at an image on the LCD on the back of the camera when images are recorded as "raw" files. This preview is also what many photo applications will show when you are viewing thumbnails of raw image files on your computer.

      • A fresh interpretation of the raw image data by a raw processing application such as Lightroom. Depending on your program settings, when you first open a raw image file, you may see either the jpeg preview image or you may see a new conversion of the raw data based on the current settings of the application with which you opened the image file. If you are seeing a fresh interpretation of the raw image data, it is still in a form that has had the same type of processing applied to it that a jpeg image produced with the same settings would have had.


      The thing to keep in mind is that there is no single interpretation of a raw image file that is "THE raw image." Raw data must be processed to be viewed as any meaningful image. The settings of the various processing steps will determine how the result looks. There is no single inherently "correct" way to process the raw data. Things such as color temperature and white balance, contrast, white point, black point, etc. must be applied to the raw data collected by the sensor before it looks anything like what we call a "photograph."



      For more detailed discussions about what the data in a raw image file is and is not, please see these other questions here at Photography at Stack Exchange:



      RAW files store 3 colors per pixel, or only one?
      Why can software correct white balance more accurately for RAW files than it can with JPEGs?
      RAW in ACR vs JPG in ACR
      While shooting in RAW, do you have to post-process it to make the picture look good?
      Why do RAW images look worse than JPEGs in editing programs?
      Why does my Lightroom/Photoshop preview change after loading?
      Why is Lightroom changing all the settings on my imported RAWs?



      ¹ Sure, you could take a picture that contains a single pure color within the entire field of view. but most photos contain a wide variation of hues, tints, and brightness levels.






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        5 Answers
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        5 Answers
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        up vote
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        Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?




        If you have a JPEG file, then it is not a RAW file.



        RAW isn't a single format, but rather a collective name for image files that contain data straight from the sensor. RAW files need to be processed in order to convert them to more general-purpose image formats like JPEG or PNG. Most cameras can do that processing themselves, so that they save their images in JPEG format, or they can write the RAW data into a file for processing on your computer. Either way, if you know your file is a JPEG file, then by definition it is not a RAW file.






        share|improve this answer



























          up vote
          50
          down vote














          Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?




          If you have a JPEG file, then it is not a RAW file.



          RAW isn't a single format, but rather a collective name for image files that contain data straight from the sensor. RAW files need to be processed in order to convert them to more general-purpose image formats like JPEG or PNG. Most cameras can do that processing themselves, so that they save their images in JPEG format, or they can write the RAW data into a file for processing on your computer. Either way, if you know your file is a JPEG file, then by definition it is not a RAW file.






          share|improve this answer

























            up vote
            50
            down vote










            up vote
            50
            down vote










            Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?




            If you have a JPEG file, then it is not a RAW file.



            RAW isn't a single format, but rather a collective name for image files that contain data straight from the sensor. RAW files need to be processed in order to convert them to more general-purpose image formats like JPEG or PNG. Most cameras can do that processing themselves, so that they save their images in JPEG format, or they can write the RAW data into a file for processing on your computer. Either way, if you know your file is a JPEG file, then by definition it is not a RAW file.






            share|improve this answer















            Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?




            If you have a JPEG file, then it is not a RAW file.



            RAW isn't a single format, but rather a collective name for image files that contain data straight from the sensor. RAW files need to be processed in order to convert them to more general-purpose image formats like JPEG or PNG. Most cameras can do that processing themselves, so that they save their images in JPEG format, or they can write the RAW data into a file for processing on your computer. Either way, if you know your file is a JPEG file, then by definition it is not a RAW file.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited yesterday

























            answered yesterday









            Caleb

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            28.9k552106
























                up vote
                22
                down vote













                Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc.), .nef (Nikon), .cr2 (Canon)...



                A JPEG file will always have the text JFIF somewhere near the start if opened in a text or hex editor, among the hieroglyphs (warning: if opening a non-text file in a text editor, NEVER save!). It is not impossible but extremely unlikely for a RAW file to have that.



                If you cannot see file name extensions in Microsoft Windows, uncheck "Folder Options"/"Hide extensions for known file types".






                share|improve this answer



















                • 5




                  The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                  – xenoid
                  yesterday








                • 3




                  @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                  – Cornstalks
                  yesterday










                • "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                  – rackandboneman
                  yesterday








                • 1




                  I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                  – xenoid
                  yesterday






                • 6




                  @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                  – Ilmari Karonen
                  yesterday

















                up vote
                22
                down vote













                Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc.), .nef (Nikon), .cr2 (Canon)...



                A JPEG file will always have the text JFIF somewhere near the start if opened in a text or hex editor, among the hieroglyphs (warning: if opening a non-text file in a text editor, NEVER save!). It is not impossible but extremely unlikely for a RAW file to have that.



                If you cannot see file name extensions in Microsoft Windows, uncheck "Folder Options"/"Hide extensions for known file types".






                share|improve this answer



















                • 5




                  The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                  – xenoid
                  yesterday








                • 3




                  @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                  – Cornstalks
                  yesterday










                • "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                  – rackandboneman
                  yesterday








                • 1




                  I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                  – xenoid
                  yesterday






                • 6




                  @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                  – Ilmari Karonen
                  yesterday















                up vote
                22
                down vote










                up vote
                22
                down vote









                Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc.), .nef (Nikon), .cr2 (Canon)...



                A JPEG file will always have the text JFIF somewhere near the start if opened in a text or hex editor, among the hieroglyphs (warning: if opening a non-text file in a text editor, NEVER save!). It is not impossible but extremely unlikely for a RAW file to have that.



                If you cannot see file name extensions in Microsoft Windows, uncheck "Folder Options"/"Hide extensions for known file types".






                share|improve this answer














                Unless somebody frivolously renamed a RAW file, it will never have a file name with the .jpg/.jpeg/.jfif extension. Typical extensions for RAW files will be .raw, .arw (Sony), .dng (Android phones etc.), .nef (Nikon), .cr2 (Canon)...



                A JPEG file will always have the text JFIF somewhere near the start if opened in a text or hex editor, among the hieroglyphs (warning: if opening a non-text file in a text editor, NEVER save!). It is not impossible but extremely unlikely for a RAW file to have that.



                If you cannot see file name extensions in Microsoft Windows, uncheck "Folder Options"/"Hide extensions for known file types".







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited yesterday









                dav1dsm1th

                1,04921215




                1,04921215










                answered yesterday









                rackandboneman

                889210




                889210








                • 5




                  The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                  – xenoid
                  yesterday








                • 3




                  @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                  – Cornstalks
                  yesterday










                • "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                  – rackandboneman
                  yesterday








                • 1




                  I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                  – xenoid
                  yesterday






                • 6




                  @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                  – Ilmari Karonen
                  yesterday
















                • 5




                  The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                  – xenoid
                  yesterday








                • 3




                  @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                  – Cornstalks
                  yesterday










                • "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                  – rackandboneman
                  yesterday








                • 1




                  I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                  – xenoid
                  yesterday






                • 6




                  @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                  – Ilmari Karonen
                  yesterday










                5




                5




                The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                – xenoid
                yesterday






                The JFIF criterion doesn't work for the JPG from my three Canon cameras (Ixus 150, 450D, 70D) or my smartphone (Moto G). No JFIF in there, Linux file says: IMG_1385.JPG: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description= , manufacturer=Canon, model=Canon IXUS 150, orientation=upper-left, xresolution=200, yresolution=208, resolutionunit=2, datetime=2018:04:17 14:52:46, GPS-Data], baseline, precision 8, 4608x3456, frames 3. Conversely, you find the JFIF in a RAW file if there is an embedded JPG thumbnail.
                – xenoid
                yesterday






                3




                3




                @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                – Cornstalks
                yesterday




                @xenoid: file isn't a text/hex editor. Try xxd (but you probably don't want to dump the whole file, so I recommend limiting it (e.g. xxd -l 1024 <file>)).
                – Cornstalks
                yesterday












                "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                – rackandboneman
                yesterday






                "file" will only be available on a unix or cygwin box usually, or on a mac, not on a standard windows box?
                – rackandboneman
                yesterday






                1




                1




                I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                – xenoid
                yesterday




                I tried grep -i JFIF *.JPG on whole directories. The only hits are on files I edited (so the image editor does use the JFIF format). I suspect this is because cameras use the Exif format and not the older JFIF format.
                – xenoid
                yesterday




                6




                6




                @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                – Ilmari Karonen
                yesterday






                @xenoid is right, Exif images have the string "Exif" instead of "JFIF" at the beginning of the first chunk. Some cameras or programs may create hybrid JFIF/Exif image files that contain both chunks, but those don't really comply with the Exif standard.
                – Ilmari Karonen
                yesterday












                up vote
                9
                down vote














                1. File ending: JPEGs end with .jpg or .jpeg, RAWs end with different strings (e.g. .cr2, .nef, .arw, ...)


                2. File headers: Usually, formats put some signature in there that tells programs.


                3. Size: Given the same size and motive, even quality 100 JPEGs will be significantly smaller. (e.g. 20 MiB vs 5 MiB)


                4. Ask a program that knows. Most (if not all) programs use the file header or other file-analyses to determine a file's format. IrfanView even tells you when you have a JPEG with a wrong ending (e.g. .png)





                There are more methods, but most involve some experience in this kind of stuff (e.g. a HEX-editor). If you want the answer to be low-level, then I would suggest to move it over to superuser.






                share|improve this answer



















                • 1




                  At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                  – Tetsujin
                  yesterday






                • 1




                  @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                  – flolilolilo
                  yesterday






                • 2




                  I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                  – Tetsujin
                  yesterday










                • @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                  – flolilolilo
                  yesterday










                • @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                  – flolilolilo
                  yesterday















                up vote
                9
                down vote














                1. File ending: JPEGs end with .jpg or .jpeg, RAWs end with different strings (e.g. .cr2, .nef, .arw, ...)


                2. File headers: Usually, formats put some signature in there that tells programs.


                3. Size: Given the same size and motive, even quality 100 JPEGs will be significantly smaller. (e.g. 20 MiB vs 5 MiB)


                4. Ask a program that knows. Most (if not all) programs use the file header or other file-analyses to determine a file's format. IrfanView even tells you when you have a JPEG with a wrong ending (e.g. .png)





                There are more methods, but most involve some experience in this kind of stuff (e.g. a HEX-editor). If you want the answer to be low-level, then I would suggest to move it over to superuser.






                share|improve this answer



















                • 1




                  At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                  – Tetsujin
                  yesterday






                • 1




                  @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                  – flolilolilo
                  yesterday






                • 2




                  I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                  – Tetsujin
                  yesterday










                • @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                  – flolilolilo
                  yesterday










                • @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                  – flolilolilo
                  yesterday













                up vote
                9
                down vote










                up vote
                9
                down vote










                1. File ending: JPEGs end with .jpg or .jpeg, RAWs end with different strings (e.g. .cr2, .nef, .arw, ...)


                2. File headers: Usually, formats put some signature in there that tells programs.


                3. Size: Given the same size and motive, even quality 100 JPEGs will be significantly smaller. (e.g. 20 MiB vs 5 MiB)


                4. Ask a program that knows. Most (if not all) programs use the file header or other file-analyses to determine a file's format. IrfanView even tells you when you have a JPEG with a wrong ending (e.g. .png)





                There are more methods, but most involve some experience in this kind of stuff (e.g. a HEX-editor). If you want the answer to be low-level, then I would suggest to move it over to superuser.






                share|improve this answer















                1. File ending: JPEGs end with .jpg or .jpeg, RAWs end with different strings (e.g. .cr2, .nef, .arw, ...)


                2. File headers: Usually, formats put some signature in there that tells programs.


                3. Size: Given the same size and motive, even quality 100 JPEGs will be significantly smaller. (e.g. 20 MiB vs 5 MiB)


                4. Ask a program that knows. Most (if not all) programs use the file header or other file-analyses to determine a file's format. IrfanView even tells you when you have a JPEG with a wrong ending (e.g. .png)





                There are more methods, but most involve some experience in this kind of stuff (e.g. a HEX-editor). If you want the answer to be low-level, then I would suggest to move it over to superuser.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited yesterday

























                answered yesterday









                flolilolilo

                4,24511633




                4,24511633








                • 1




                  At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                  – Tetsujin
                  yesterday






                • 1




                  @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                  – flolilolilo
                  yesterday






                • 2




                  I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                  – Tetsujin
                  yesterday










                • @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                  – flolilolilo
                  yesterday










                • @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                  – flolilolilo
                  yesterday














                • 1




                  At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                  – Tetsujin
                  yesterday






                • 1




                  @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                  – flolilolilo
                  yesterday






                • 2




                  I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                  – Tetsujin
                  yesterday










                • @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                  – flolilolilo
                  yesterday










                • @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                  – flolilolilo
                  yesterday








                1




                1




                At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                – Tetsujin
                yesterday




                At a guess... perhaps more relevant to the OP is that whilst a RAW can be re-processed into a JPG [or PNG etc] you cannot do it the other way, you cannot reprocess a jpg back to a raw.
                – Tetsujin
                yesterday




                1




                1




                @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                – flolilolilo
                yesterday




                @Tetsujin That is true, but it makes a terrible mess of identifying formats :-)
                – flolilolilo
                yesterday




                2




                2




                I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                – Tetsujin
                yesterday




                I'm thinking there's a comprehension issue at root - "Once I've a JPEG photograph image file, how can I find out whether it is a RAW file or not?" ...at that point you don't have a RAW, you have a JPG. A RAW can contain a JPG, but a JPG cannot contain or be transmuted into a RAW.
                – Tetsujin
                yesterday












                @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                – flolilolilo
                yesterday




                @Tetsujin Aaaaah that's definitely a better way to interpret the question! Will add a few words about this. Thanks!
                – flolilolilo
                yesterday












                @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                – flolilolilo
                yesterday




                @Tetsujin ...later, that its. tried to finish it on the way, but now, work caught up with me!
                – flolilolilo
                yesterday










                up vote
                2
                down vote













                RAW format, as generally called, is a group of file types with different suffixes. There are *.raw files and proprietary files like *.cr2 for Canon, for example and many others. I am a Canoneer so the following is based on my experience with my Canon.



                Almost every manufacturer has their own RAW file format. Be also careful that some, Canon for sure, updates their RAW format so claim "All [Canon] image tools can open all [Canon] RAW images" is false. To preview a RAW file one need program that can process the the particular file format in particular version. Even mighty Photoshop have issues opening every RAW file.



                RAW file is a dump of the data collected from the sensor plus data containing the camera setups. It is complete and lossless acquisition of data from the camera to the memory. RAW format is not an image format at all.



                The cameras have built-in image processors (in case of Canon it is named DigicX) that interpret the RAW file to JPEG and show on screen and/or store to memory.



                When one use any digital camera the internal workflow is:




                1. Open the shutter (mechanical: slide first curtain away, digital: start saving the data stream from the chip)

                2. Acquire the scene

                3. Close the shutter (mechanical: slide second curtain over the chip, digital: stop saving the data stream)

                4. Dump the data acquired to the buffer

                5. Process the image to jpeg using pre-set options

                6. Show preview to the screen.

                7. Save the image

                8. Clear buffer memory.


                If the RAW mode is selected, the processor saves the data to image as-is in the body-specific format. If the RAW+JPEG mode is selected, processor saves the data as-is to image.cr2 (for Canons) and processed image to image.jpeg. If JPEG mode is selected only the processed image is saved and the raw data are lost forever.



                That's why the RAW images are humongous when compared to true image formats. If you have 12MPx camera with 16bit depth the RAW file holds 12 000 000 * 16 bits of image information plus negligible amount of data keeping the setups.



                JPEG is, on the other hand, file format dedicated to store images in files with reasonably size. It is based on lossy compression and benefits from the fact, that 50 shades of black are black to human eye, so why bother? It works similarly to .mp3 audio format - it ignores the nuances the detector can distinguish but human senses can't. The level of ignorance is regulated by the compression quality.



                How to identify RAW files?




                • They are humongous

                • Few previewers can process them

                • The file extension is not jpg or jpeg






                share|improve this answer



























                  up vote
                  2
                  down vote













                  RAW format, as generally called, is a group of file types with different suffixes. There are *.raw files and proprietary files like *.cr2 for Canon, for example and many others. I am a Canoneer so the following is based on my experience with my Canon.



                  Almost every manufacturer has their own RAW file format. Be also careful that some, Canon for sure, updates their RAW format so claim "All [Canon] image tools can open all [Canon] RAW images" is false. To preview a RAW file one need program that can process the the particular file format in particular version. Even mighty Photoshop have issues opening every RAW file.



                  RAW file is a dump of the data collected from the sensor plus data containing the camera setups. It is complete and lossless acquisition of data from the camera to the memory. RAW format is not an image format at all.



                  The cameras have built-in image processors (in case of Canon it is named DigicX) that interpret the RAW file to JPEG and show on screen and/or store to memory.



                  When one use any digital camera the internal workflow is:




                  1. Open the shutter (mechanical: slide first curtain away, digital: start saving the data stream from the chip)

                  2. Acquire the scene

                  3. Close the shutter (mechanical: slide second curtain over the chip, digital: stop saving the data stream)

                  4. Dump the data acquired to the buffer

                  5. Process the image to jpeg using pre-set options

                  6. Show preview to the screen.

                  7. Save the image

                  8. Clear buffer memory.


                  If the RAW mode is selected, the processor saves the data to image as-is in the body-specific format. If the RAW+JPEG mode is selected, processor saves the data as-is to image.cr2 (for Canons) and processed image to image.jpeg. If JPEG mode is selected only the processed image is saved and the raw data are lost forever.



                  That's why the RAW images are humongous when compared to true image formats. If you have 12MPx camera with 16bit depth the RAW file holds 12 000 000 * 16 bits of image information plus negligible amount of data keeping the setups.



                  JPEG is, on the other hand, file format dedicated to store images in files with reasonably size. It is based on lossy compression and benefits from the fact, that 50 shades of black are black to human eye, so why bother? It works similarly to .mp3 audio format - it ignores the nuances the detector can distinguish but human senses can't. The level of ignorance is regulated by the compression quality.



                  How to identify RAW files?




                  • They are humongous

                  • Few previewers can process them

                  • The file extension is not jpg or jpeg






                  share|improve this answer

























                    up vote
                    2
                    down vote










                    up vote
                    2
                    down vote









                    RAW format, as generally called, is a group of file types with different suffixes. There are *.raw files and proprietary files like *.cr2 for Canon, for example and many others. I am a Canoneer so the following is based on my experience with my Canon.



                    Almost every manufacturer has their own RAW file format. Be also careful that some, Canon for sure, updates their RAW format so claim "All [Canon] image tools can open all [Canon] RAW images" is false. To preview a RAW file one need program that can process the the particular file format in particular version. Even mighty Photoshop have issues opening every RAW file.



                    RAW file is a dump of the data collected from the sensor plus data containing the camera setups. It is complete and lossless acquisition of data from the camera to the memory. RAW format is not an image format at all.



                    The cameras have built-in image processors (in case of Canon it is named DigicX) that interpret the RAW file to JPEG and show on screen and/or store to memory.



                    When one use any digital camera the internal workflow is:




                    1. Open the shutter (mechanical: slide first curtain away, digital: start saving the data stream from the chip)

                    2. Acquire the scene

                    3. Close the shutter (mechanical: slide second curtain over the chip, digital: stop saving the data stream)

                    4. Dump the data acquired to the buffer

                    5. Process the image to jpeg using pre-set options

                    6. Show preview to the screen.

                    7. Save the image

                    8. Clear buffer memory.


                    If the RAW mode is selected, the processor saves the data to image as-is in the body-specific format. If the RAW+JPEG mode is selected, processor saves the data as-is to image.cr2 (for Canons) and processed image to image.jpeg. If JPEG mode is selected only the processed image is saved and the raw data are lost forever.



                    That's why the RAW images are humongous when compared to true image formats. If you have 12MPx camera with 16bit depth the RAW file holds 12 000 000 * 16 bits of image information plus negligible amount of data keeping the setups.



                    JPEG is, on the other hand, file format dedicated to store images in files with reasonably size. It is based on lossy compression and benefits from the fact, that 50 shades of black are black to human eye, so why bother? It works similarly to .mp3 audio format - it ignores the nuances the detector can distinguish but human senses can't. The level of ignorance is regulated by the compression quality.



                    How to identify RAW files?




                    • They are humongous

                    • Few previewers can process them

                    • The file extension is not jpg or jpeg






                    share|improve this answer














                    RAW format, as generally called, is a group of file types with different suffixes. There are *.raw files and proprietary files like *.cr2 for Canon, for example and many others. I am a Canoneer so the following is based on my experience with my Canon.



                    Almost every manufacturer has their own RAW file format. Be also careful that some, Canon for sure, updates their RAW format so claim "All [Canon] image tools can open all [Canon] RAW images" is false. To preview a RAW file one need program that can process the the particular file format in particular version. Even mighty Photoshop have issues opening every RAW file.



                    RAW file is a dump of the data collected from the sensor plus data containing the camera setups. It is complete and lossless acquisition of data from the camera to the memory. RAW format is not an image format at all.



                    The cameras have built-in image processors (in case of Canon it is named DigicX) that interpret the RAW file to JPEG and show on screen and/or store to memory.



                    When one use any digital camera the internal workflow is:




                    1. Open the shutter (mechanical: slide first curtain away, digital: start saving the data stream from the chip)

                    2. Acquire the scene

                    3. Close the shutter (mechanical: slide second curtain over the chip, digital: stop saving the data stream)

                    4. Dump the data acquired to the buffer

                    5. Process the image to jpeg using pre-set options

                    6. Show preview to the screen.

                    7. Save the image

                    8. Clear buffer memory.


                    If the RAW mode is selected, the processor saves the data to image as-is in the body-specific format. If the RAW+JPEG mode is selected, processor saves the data as-is to image.cr2 (for Canons) and processed image to image.jpeg. If JPEG mode is selected only the processed image is saved and the raw data are lost forever.



                    That's why the RAW images are humongous when compared to true image formats. If you have 12MPx camera with 16bit depth the RAW file holds 12 000 000 * 16 bits of image information plus negligible amount of data keeping the setups.



                    JPEG is, on the other hand, file format dedicated to store images in files with reasonably size. It is based on lossy compression and benefits from the fact, that 50 shades of black are black to human eye, so why bother? It works similarly to .mp3 audio format - it ignores the nuances the detector can distinguish but human senses can't. The level of ignorance is regulated by the compression quality.



                    How to identify RAW files?




                    • They are humongous

                    • Few previewers can process them

                    • The file extension is not jpg or jpeg







                    share|improve this answer














                    share|improve this answer



                    share|improve this answer








                    edited yesterday









                    xiota

                    7,65921447




                    7,65921447










                    answered yesterday









                    Crowley

                    1,585511




                    1,585511






















                        up vote
                        0
                        down vote













                        Raw image files contain enough data to create a near infinite number of interpretations of that data that will fit in an 8-bit jpeg file.¹ Anytime you open a raw file and look at it on your screen, you are not viewing "THE raw file." You are viewing one among countless possible interpretations of the data in the raw file. The raw data itself contains a single (monochrome) brightness value measure by each pixel well. With Bayer masked camera sensors (the vast majority of color digital cameras use Bayer filters) each pixel well has a color filter in front of it that is either red, green, or blue. For a more complete discussion of how we get color information out of the single brightness values measured at each pixel well, please see RAW files store 3 colors per pixel, or only one?



                        How the image you see on your monitor when you open a raw file will look is determined by how the application you used to open the file chose to interpret the raw data in the file to produce a viewable image. Each application has its own set of default parameters that determine how the raw data is processed. One of the most significant parameters is how the white balance that is used to convert the raw data is selected. Most applications have many different sets of parameters that can be selected by the user, who is then free to alter individual settings within the set of instructions used to initially interpret the data in the raw file.



                        If you are viewing an image on a screen, you are not looking at a raw file. What you are seeing is one possible interpretation of the raw data collected by a camera sensor. That interpretation may be one of several things:




                        • A jpeg produced by the camera using the raw data from the sensor and the camera's settings current at the time the image was captured.

                        • A jpeg preview image attached to a raw image file. The jpeg preview is also produced by the camera's internal processor using the camera's settings current at the time the image was captured. It is attached to the raw image file. This preview is normally what one sees when looking at an image on the LCD on the back of the camera when images are recorded as "raw" files. This preview is also what many photo applications will show when you are viewing thumbnails of raw image files on your computer.

                        • A fresh interpretation of the raw image data by a raw processing application such as Lightroom. Depending on your program settings, when you first open a raw image file, you may see either the jpeg preview image or you may see a new conversion of the raw data based on the current settings of the application with which you opened the image file. If you are seeing a fresh interpretation of the raw image data, it is still in a form that has had the same type of processing applied to it that a jpeg image produced with the same settings would have had.


                        The thing to keep in mind is that there is no single interpretation of a raw image file that is "THE raw image." Raw data must be processed to be viewed as any meaningful image. The settings of the various processing steps will determine how the result looks. There is no single inherently "correct" way to process the raw data. Things such as color temperature and white balance, contrast, white point, black point, etc. must be applied to the raw data collected by the sensor before it looks anything like what we call a "photograph."



                        For more detailed discussions about what the data in a raw image file is and is not, please see these other questions here at Photography at Stack Exchange:



                        RAW files store 3 colors per pixel, or only one?
                        Why can software correct white balance more accurately for RAW files than it can with JPEGs?
                        RAW in ACR vs JPG in ACR
                        While shooting in RAW, do you have to post-process it to make the picture look good?
                        Why do RAW images look worse than JPEGs in editing programs?
                        Why does my Lightroom/Photoshop preview change after loading?
                        Why is Lightroom changing all the settings on my imported RAWs?



                        ¹ Sure, you could take a picture that contains a single pure color within the entire field of view. but most photos contain a wide variation of hues, tints, and brightness levels.






                        share|improve this answer

























                          up vote
                          0
                          down vote













                          Raw image files contain enough data to create a near infinite number of interpretations of that data that will fit in an 8-bit jpeg file.¹ Anytime you open a raw file and look at it on your screen, you are not viewing "THE raw file." You are viewing one among countless possible interpretations of the data in the raw file. The raw data itself contains a single (monochrome) brightness value measure by each pixel well. With Bayer masked camera sensors (the vast majority of color digital cameras use Bayer filters) each pixel well has a color filter in front of it that is either red, green, or blue. For a more complete discussion of how we get color information out of the single brightness values measured at each pixel well, please see RAW files store 3 colors per pixel, or only one?



                          How the image you see on your monitor when you open a raw file will look is determined by how the application you used to open the file chose to interpret the raw data in the file to produce a viewable image. Each application has its own set of default parameters that determine how the raw data is processed. One of the most significant parameters is how the white balance that is used to convert the raw data is selected. Most applications have many different sets of parameters that can be selected by the user, who is then free to alter individual settings within the set of instructions used to initially interpret the data in the raw file.



                          If you are viewing an image on a screen, you are not looking at a raw file. What you are seeing is one possible interpretation of the raw data collected by a camera sensor. That interpretation may be one of several things:




                          • A jpeg produced by the camera using the raw data from the sensor and the camera's settings current at the time the image was captured.

                          • A jpeg preview image attached to a raw image file. The jpeg preview is also produced by the camera's internal processor using the camera's settings current at the time the image was captured. It is attached to the raw image file. This preview is normally what one sees when looking at an image on the LCD on the back of the camera when images are recorded as "raw" files. This preview is also what many photo applications will show when you are viewing thumbnails of raw image files on your computer.

                          • A fresh interpretation of the raw image data by a raw processing application such as Lightroom. Depending on your program settings, when you first open a raw image file, you may see either the jpeg preview image or you may see a new conversion of the raw data based on the current settings of the application with which you opened the image file. If you are seeing a fresh interpretation of the raw image data, it is still in a form that has had the same type of processing applied to it that a jpeg image produced with the same settings would have had.


                          The thing to keep in mind is that there is no single interpretation of a raw image file that is "THE raw image." Raw data must be processed to be viewed as any meaningful image. The settings of the various processing steps will determine how the result looks. There is no single inherently "correct" way to process the raw data. Things such as color temperature and white balance, contrast, white point, black point, etc. must be applied to the raw data collected by the sensor before it looks anything like what we call a "photograph."



                          For more detailed discussions about what the data in a raw image file is and is not, please see these other questions here at Photography at Stack Exchange:



                          RAW files store 3 colors per pixel, or only one?
                          Why can software correct white balance more accurately for RAW files than it can with JPEGs?
                          RAW in ACR vs JPG in ACR
                          While shooting in RAW, do you have to post-process it to make the picture look good?
                          Why do RAW images look worse than JPEGs in editing programs?
                          Why does my Lightroom/Photoshop preview change after loading?
                          Why is Lightroom changing all the settings on my imported RAWs?



                          ¹ Sure, you could take a picture that contains a single pure color within the entire field of view. but most photos contain a wide variation of hues, tints, and brightness levels.






                          share|improve this answer























                            up vote
                            0
                            down vote










                            up vote
                            0
                            down vote









                            Raw image files contain enough data to create a near infinite number of interpretations of that data that will fit in an 8-bit jpeg file.¹ Anytime you open a raw file and look at it on your screen, you are not viewing "THE raw file." You are viewing one among countless possible interpretations of the data in the raw file. The raw data itself contains a single (monochrome) brightness value measure by each pixel well. With Bayer masked camera sensors (the vast majority of color digital cameras use Bayer filters) each pixel well has a color filter in front of it that is either red, green, or blue. For a more complete discussion of how we get color information out of the single brightness values measured at each pixel well, please see RAW files store 3 colors per pixel, or only one?



                            How the image you see on your monitor when you open a raw file will look is determined by how the application you used to open the file chose to interpret the raw data in the file to produce a viewable image. Each application has its own set of default parameters that determine how the raw data is processed. One of the most significant parameters is how the white balance that is used to convert the raw data is selected. Most applications have many different sets of parameters that can be selected by the user, who is then free to alter individual settings within the set of instructions used to initially interpret the data in the raw file.



                            If you are viewing an image on a screen, you are not looking at a raw file. What you are seeing is one possible interpretation of the raw data collected by a camera sensor. That interpretation may be one of several things:




                            • A jpeg produced by the camera using the raw data from the sensor and the camera's settings current at the time the image was captured.

                            • A jpeg preview image attached to a raw image file. The jpeg preview is also produced by the camera's internal processor using the camera's settings current at the time the image was captured. It is attached to the raw image file. This preview is normally what one sees when looking at an image on the LCD on the back of the camera when images are recorded as "raw" files. This preview is also what many photo applications will show when you are viewing thumbnails of raw image files on your computer.

                            • A fresh interpretation of the raw image data by a raw processing application such as Lightroom. Depending on your program settings, when you first open a raw image file, you may see either the jpeg preview image or you may see a new conversion of the raw data based on the current settings of the application with which you opened the image file. If you are seeing a fresh interpretation of the raw image data, it is still in a form that has had the same type of processing applied to it that a jpeg image produced with the same settings would have had.


                            The thing to keep in mind is that there is no single interpretation of a raw image file that is "THE raw image." Raw data must be processed to be viewed as any meaningful image. The settings of the various processing steps will determine how the result looks. There is no single inherently "correct" way to process the raw data. Things such as color temperature and white balance, contrast, white point, black point, etc. must be applied to the raw data collected by the sensor before it looks anything like what we call a "photograph."



                            For more detailed discussions about what the data in a raw image file is and is not, please see these other questions here at Photography at Stack Exchange:



                            RAW files store 3 colors per pixel, or only one?
                            Why can software correct white balance more accurately for RAW files than it can with JPEGs?
                            RAW in ACR vs JPG in ACR
                            While shooting in RAW, do you have to post-process it to make the picture look good?
                            Why do RAW images look worse than JPEGs in editing programs?
                            Why does my Lightroom/Photoshop preview change after loading?
                            Why is Lightroom changing all the settings on my imported RAWs?



                            ¹ Sure, you could take a picture that contains a single pure color within the entire field of view. but most photos contain a wide variation of hues, tints, and brightness levels.






                            share|improve this answer












                            Raw image files contain enough data to create a near infinite number of interpretations of that data that will fit in an 8-bit jpeg file.¹ Anytime you open a raw file and look at it on your screen, you are not viewing "THE raw file." You are viewing one among countless possible interpretations of the data in the raw file. The raw data itself contains a single (monochrome) brightness value measure by each pixel well. With Bayer masked camera sensors (the vast majority of color digital cameras use Bayer filters) each pixel well has a color filter in front of it that is either red, green, or blue. For a more complete discussion of how we get color information out of the single brightness values measured at each pixel well, please see RAW files store 3 colors per pixel, or only one?



                            How the image you see on your monitor when you open a raw file will look is determined by how the application you used to open the file chose to interpret the raw data in the file to produce a viewable image. Each application has its own set of default parameters that determine how the raw data is processed. One of the most significant parameters is how the white balance that is used to convert the raw data is selected. Most applications have many different sets of parameters that can be selected by the user, who is then free to alter individual settings within the set of instructions used to initially interpret the data in the raw file.



                            If you are viewing an image on a screen, you are not looking at a raw file. What you are seeing is one possible interpretation of the raw data collected by a camera sensor. That interpretation may be one of several things:




                            • A jpeg produced by the camera using the raw data from the sensor and the camera's settings current at the time the image was captured.

                            • A jpeg preview image attached to a raw image file. The jpeg preview is also produced by the camera's internal processor using the camera's settings current at the time the image was captured. It is attached to the raw image file. This preview is normally what one sees when looking at an image on the LCD on the back of the camera when images are recorded as "raw" files. This preview is also what many photo applications will show when you are viewing thumbnails of raw image files on your computer.

                            • A fresh interpretation of the raw image data by a raw processing application such as Lightroom. Depending on your program settings, when you first open a raw image file, you may see either the jpeg preview image or you may see a new conversion of the raw data based on the current settings of the application with which you opened the image file. If you are seeing a fresh interpretation of the raw image data, it is still in a form that has had the same type of processing applied to it that a jpeg image produced with the same settings would have had.


                            The thing to keep in mind is that there is no single interpretation of a raw image file that is "THE raw image." Raw data must be processed to be viewed as any meaningful image. The settings of the various processing steps will determine how the result looks. There is no single inherently "correct" way to process the raw data. Things such as color temperature and white balance, contrast, white point, black point, etc. must be applied to the raw data collected by the sensor before it looks anything like what we call a "photograph."



                            For more detailed discussions about what the data in a raw image file is and is not, please see these other questions here at Photography at Stack Exchange:



                            RAW files store 3 colors per pixel, or only one?
                            Why can software correct white balance more accurately for RAW files than it can with JPEGs?
                            RAW in ACR vs JPG in ACR
                            While shooting in RAW, do you have to post-process it to make the picture look good?
                            Why do RAW images look worse than JPEGs in editing programs?
                            Why does my Lightroom/Photoshop preview change after loading?
                            Why is Lightroom changing all the settings on my imported RAWs?



                            ¹ Sure, you could take a picture that contains a single pure color within the entire field of view. but most photos contain a wide variation of hues, tints, and brightness levels.







                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered yesterday









                            Michael C

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