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Thread: PSCS2: tif to jpeg, color changes

  1. #1

    Default PSCS2: tif to jpeg, color changes

    Hi People,

    I shoot in RAW with my E1, and develop the raw using olympus viewer to 16bit tiff. From the tiff, I use save for the web option to convert to jpeg. I included the ICC profile and used maximum settings but after saving the jpeg, I find that there are color changes. Is it because of the 16bit to 8bit conversion?? I thought the color should be consistent between the tiff anf jpeg..

    Do you guys have the same problem? Any solution?

  2. #2
    Senior Member +evenstar's Avatar
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    Default Re: PSCS2: tif to jpeg, color changes

    Are you shooting in Adobe RGB or SRGB?
    eat. drink. shoot

  3. #3

    Default Re: PSCS2: tif to jpeg, color changes

    adobe RGB but I included the color profile in the Jpeg

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    Senior Member +evenstar's Avatar
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    Default Re: PSCS2: tif to jpeg, color changes

    Quote Originally Posted by wind30
    adobe RGB but I included the color profile in the Jpeg
    Are you using photoshop to view the images?
    eat. drink. shoot

  5. #5

    Default Re: PSCS2: tif to jpeg, color changes

    using adobe bridge. I think it is ICC aware.

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    Senior Member +evenstar's Avatar
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    Default Re: PSCS2: tif to jpeg, color changes

    I think it's because u used the "save for web" function, which only allows saving in sRGB. Hence, if you save a Adobe RGB image "for web", colours will turn out very flat. Maybe you try converting it to sRGB first before saving?
    eat. drink. shoot

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    Default Re: PSCS2: tif to jpeg, color changes

    Quote Originally Posted by +evenstar
    I think it's because u used the "save for web" function, which only allows saving in sRGB. Hence, if you save a Adobe RGB image "for web", colours will turn out very flat. Maybe you try converting it to sRGB first before saving?
    JPEG has defined a whole range of compression/transmission standards. Image file formats that use these standards may differ even more. (A TIFF file may for example use JPEG compression to store image data).

    The universally accepted baseline JPEG file format is JFIF. JFIF uses the CCIR 601 YCbCr colour space, not sRGB. In general, no JPEG-DCT compressed image format uses RGB, since one of the major compression principles is based on separating luminance and chrominance (brightness and colour).

    There are some file formats losely based on JFIF (e.g. EXIF) that may allow to use other colour spaces and embed colour profiles. Strictly speaking, programs expecting proper JFIF files should reject such files. (If such a file claims it is JFIF, but uses a different colour space, it resp. the program that generated it is broken.) However, in the interest of "user-friendlyness", most JFIF decoders will try to interpret these files as if they were JFIF files, which could result e.g. in colour shifts etc.

    Edit: this link is probably the best starting point: http://www.jpeg.org/jpeg/index.html
    Last edited by LittleWolf; 17th December 2005 at 03:41 PM.

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    Default Re: PSCS2: tif to jpeg, color changes

    Quote Originally Posted by wind30
    From the tiff, I use save for the web option to convert to jpeg.
    Are you by chance using Photoshop CS to do this?

    I just looked at two ".jpg" files generated by Photoshop CS. Both are a mish-mash of JFIF and EXIF. The file header claims they are JFIF version 1.02, however there are also EXIF APP1 marker segments, which are not allowed in JFIF files. An EXIF file, in turn, should not have an JFIF 1.02 file header.

    In other words, Photshop CS is most likely broken. You could try using standards compliant software and see if that solves your problem.

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