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Color profile conversion

Posted: 2009-05-14T02:19:20-07:00
by olafvdg
I am running this command:
convert test.jpg -profile rgb.icc -profile cmyk.icc cmyk_test.jpg

It runs perfect on a webserver with the old IM version 6.2.4, but it fails to do a proper conversion on the slightly newer 6.2.5

The new profile gets attached, but there is no actual conversion on 6.2.5, whereas 6.2.4. does the job fine.

Since these are commercially hosted sites I do not have control over the version...
Is there any way to get 6.2.5 to do the job just like 6.2.4 does...

Thanks for the help!

Re: Color profile conversion

Posted: 2009-05-14T09:19:20-07:00
by fmw42
If you really believe this is a bug, then you should post it with your images and profiles to the bugs forum at viewforum.php?f=3

Re: Color profile conversion

Posted: 2009-05-14T22:53:54-07:00
by anthony
Are the profiles (which are external to IM) actually installed on the machine with the newer version?

Re: Color profile conversion

Posted: 2009-05-18T03:08:09-07:00
by olafvdg
Yes, profiles are installed and the cmyk profile is even attached to the new image as identify -verbose shows.
It just seems that the profile is attached without any conversion taking place....

Any ideas?

Re: Color profile conversion

Posted: 2009-05-18T16:38:20-07:00
by anthony
If the image does not have a profile, the first profile option will attach one, then the second will do the conversion.

If the image does have a profile attached the first profile option will do the conversion.





Sometimes I think a warning should be given if no color profile was present when the first profile is attached. EG something like
WARNING: no existing color profile found, attaching given profile without color conversion
Of course a -quiet operational flag will then not give the warning, while a -regard-warnings flag would cause IM to terminate with an error in that case (allowing scripts to try a second time using -quiet, and provide two profiles with a guess at the current color profile of the image)

Re: Color profile conversion

Posted: 2009-05-19T01:06:14-07:00
by olafvdg
Hi anthony,

But still that's not the problem.

I have also tried:
convert test.jpg -strip -profile "rgb.icc" -profile "cmyk.icc" cmyk_test.jpg
to strip out all profile information first.

Also in this case, the cmyk profile is attached but the colorspace of the image is still RGB, indicating no actual conversion took place.

Any further suggestions?

Re: Color profile conversion

Posted: 2009-05-19T16:21:22-07:00
by anthony
No sorry. As I mentioned before I don't use color profiles myself. I have only seem a lot of people with similar problems caused by color profiles, and have noted information on this. It certainaly sounded like the problem you were experiencing.