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Archive 2013 · Color shift / change during resize to small jpeg

  
 
billsnature
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p.1 #1 · p.1 #1 · Color shift / change during resize to small jpeg


I searched this forum for color shift and color change and didn't find my answer, so let me ask directly.

I am resizing some images to make a much smaller file size for posting on pbase. Going from a Photoshop PSD or a very large JPEG to a much smaller JPEG. I have tried a couple of different tools, (Photoshop 6 save as JPEG quality 2 and MS photoediter resize letter small) and in every case where I get pretty small I get a big color shift when I hit the save button. Like the sky going from blue to turquoise. What causes that and how do I stop it? Pictures of an eagle in flight in a blue sky, suddenly look like an eagle swimming in the Bahamas.

This is not a pbase problem so no pbase rants please....I see the issue before uploading to pbase.

Thanks in advance for your help

Bill



Jan 16, 2013 at 08:41 PM
Peter Figen
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p.1 #2 · p.1 #2 · Color shift / change during resize to small jpeg


This has nothing to do with saving as a jpeg but everything to do with color profiles, tagging images with profile, your working color space, etc. It's a color management issue. Start with a list of your exact workflow including working spaces, color management policies, the color spaces your files are/were in, etc. From there it will be pretty easy to determine where you went wrong.


Jan 16, 2013 at 08:52 PM
billsnature
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p.1 #3 · p.1 #3 · Color shift / change during resize to small jpeg


I wish it were that simple, but I don't think it is. If I save it with a JPEG quaility of 10-12 then I don't get a color shift. If I save it as a JPEG with a quaility for 2 I do get a shift.

If I take one that was saved with a JPEG quality of 10 and had no shift to tht point, and the I open it (still no shift), resize as "Doccument small" in MS photo editor, still no large shift. Hit save, big color shift as it actually resizes to save.''

The conversion from PSD to JPEG has no impact on color unless going to a sub 100K file size.



Jan 18, 2013 at 06:14 PM
Peter Figen
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p.1 #4 · p.1 #4 · Color shift / change during resize to small jpeg


If you save with a number 2 level of compression, you'll get some artifacts, but the overall color won't change. Sure, at the pixel level, individual pixels may be slightly different but that's due to the lossy compression. My guess is that MS Photo Editor, whatever that is, is your culprit. More than likely it's both not color managed and it's tossing any embedded profiles you may have had.


Jan 18, 2013 at 07:06 PM
Peter Figen
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p.1 #5 · p.1 #5 · Color shift / change during resize to small jpeg


but you could post of couple of sample images demonstrating the problem...


Jan 18, 2013 at 07:06 PM
billsnature
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p.1 #6 · p.1 #6 · Color shift / change during resize to small jpeg


here are the worst offenders

















Jan 19, 2013 at 05:33 PM





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