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    changed palette in some *.jpg

    Hi,

    since IV 4.10 some (very few) of my jpegs seem to have a changed palette. i've attached one of these files and a comparison of the IV output and how it should look like.

    IV 4.00 did not change the palette.

    i've tried to switch 'use embedded color profile for jpg/tiff' on and off - no difference.

    i'm using win 2000, IBM Thinkpad T23 with intel PIII mobile 1133 MHz, 256 MB RAM.

    anybody with similar experiences? and, is it a bug of IV or win?

    Thanks
    A

    #2
    Looks like 2 other users have reported the same bug: swapped Red and Blue channels.




    My main graphics editor Paint Shop Pro 7 also shows this problem.
    Last edited by j7n; 06.12.2007, 12:34 AM.

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      #3
      Confirmed behaviour. When enlarging the attachment it looks ok, then after saving, it's the blue one.

      I noticed a header in "architecture.jpg" which is different from the standard one, having the string "JFIF".
      This one has in the first line the strings : "Adobe -- Photoshop 3.0 -- 8BIM".
      Fourth byte differs too. Instead of E0 it's EE
      0.6180339887
      Rest In Peace, Sam!

      Comment


        #4
        Adobe must have found a way to stick its name in some essential numerical fields, not just comment or Exif... Now I remember coming across such an image with "Adobe" text in the beginning. I hate Adobe and wanted to eradicate this text by typing over it, but the file came out with wrong colors afterwards (no IV 4.1 was involved).

        I don't know the JPEG header, so to me it looks almost as if magic is involved: I erased the five letters by typing 0x20 over them, saved the file in arithmetic coding (to get as far from the original data as possible) and the text 'Adobe' came back. Weird...

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          #5
          It's a Photoshop image allright. It has an enclosed color profile, which is recognized by Photoshop, but not by IV. Some other viewers can handle your image and some don't. They all can't save it with a different profile eighter.

          I would not consider this as a IV bug though. Loading your image into Photoshop will convert it to normal RGB as it shout be. I have tried to seek at the build-in profile, but there wasn't any that gave the same blue appearance as you attached in your post. The image that you sent probably isn't saved with a usable correct RGB or CMYK colorprofile.

          Here is your image, saved from Photoshop version 6 (version 9 does the same). It has the same header (JFIF) but a different colorprofile (sRGB IEC61966-2.1) which is a standard profile. Also see the image, viewed by Compu-Pic. Even worse!
          Attached Files

          Comment


            #6
            Originally posted by Sjef View Post
            It has an enclosed color profile, which is recognized by Photoshop, but not by IV.
            The emphasis was on version 4.1. IrfanView v4.0 did load this picture with correct channel order. Perhaps older Irfan was better at handling invalid JPEGs.

            Loading your image into Photoshop will convert it to normal RGB as it shout be.
            You could also swap the Red and Blue channels in IrfanView, easily returning the original colors. The problem is that you won't do that every time an image like this is viewed.

            Comment


              #7
              Originally posted by j7n View Post
              You could also swap the Red and Blue channels in IrfanView, easily returning the original colors. The problem is that you won't do that every time an image like this is viewed.
              Thanks for remembering me about colorswapping, j7n. Indeed it's years ago I used that option.

              Comment


                #8
                didnt realize that actually the R and B channels are swapped, rather than a changed palette.

                it seems to me that its a bug of Photoshop rather than IV as Sjef suggests. this is supported by the fact that other software are also having problems with some / the same photoshop images. However there is a way around this bug as IV 4.0 and some other software demonstrates. Even if Photoshop would eradicate this bug (guess they have no interest) it wont have any effect on these pictures.

                Would it be possible to handle these type of bugged jpegs in the next version of IV in a similar manner as it was done in IV 4.0? this also should circumnavigate the request of some other users suggesting to introduce a feature swapping R and B channels.
                (also see http://en.irfanview-forum.de/vb/showthread.php?t=1166, http://en.irfanview-forum.de/vb/showthread.php?t=1161)

                thanks to all of you for your help and suggestions!
                at least now i know more about the problem. at some point i was afraid that some pics i save with IV now might have their palette changed without me noticing it at first.

                Comment


                  #9
                  I experienced the same problem when creating TIFF files with IrfanView 4.10. The color images come from a wide range of sources including Adobe (as JPEG), IBM Content Manager (Color Tiff, OLD JPEG Compression), and Kofax scanning software (as JPEG).

                  The TIFF I create have the channels swapped when merging several color image files into a single tiff with JPEG compression using the built in functionality of IrfanView.

                  I think there is a bug somewhere in IrfanView that would cause this.

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