identify: no pixels defined in cache `XXXXX' @ c

[Moonshine]

I use "identify" to check the colorspace of images on upload. Previously it had been working flawlessly, however a recent Fedora 11 update seems to have identify tossing random errors on some CMYK files being uploaded. I'm using:

Code: Select all

Version: ImageMagick 6.5.1-2 2010-01-06 Q16 OpenMP http://www.imagemagick.org
Copyright: Copyright (C) 1999-2009 ImageMagick Studio LLC

The command I use:

Code: Select all

/usr/bin/identify -quiet -format '%[colorspace]' cmyk_test_image.jpg

Results in:

Code: Select all

identify: no pixels defined in cache `cmyk_test_image.jpg' @ cache.c/OpenPixelCache/3789.
CMYK

Here is an image for testing:

http://james.netfocal.com/test/cmyk_test_image.jpg

BTW, it also looks like the copyright could use an update to 2010

[magick]

Your command works fine with the latest releases of ImageMagick. We're not sure why it fails for ImageMagick 6.5.1. We'll investigate.

[Moonshine]

Thanks for the reply.. I'll compile my own, but I would be curious what version made the correction if you happen to find out. Just so I can jump back on the Yum train again someday for these servers.

[Moonshine]

I updated a development machine here to 6.6 via the binary distribution today. Identify does work without error for me in 6.6. Excellent.

However my "convert" script (for converting the images from CMYK to RGB) seems to have very different output from 6.5.1-2 to 6.6 using the same command and profile. The output I get from 6.6 looks very washed out, like a levels or gamma shift, and the color mapping seems different also. The ouput from 6.5.1-2 is correct when compared to Photoshop CS4 and OSX preview output. An example command is like:

Code: Select all

convert test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' -profile sRGB.icc test-rgb.jpg

using the files here:

http://james.netfocal.com/imagemagick

which produces this in 6.5.1-2:



and this in 6.6:



I've tried poking around to see if there are some new options I should use, or if a new profile would help, but I can't seem to find anything to correct things. Not sure if anyone has suggestions, or if I should just open a new thread...

Thanks for any help...

[fmw42]

try

convert -colorspace RGB test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' -profile sRGB.icc test-rgb.jpg

or just

convert -colorspace RGB test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' test-rgb.jpg

The latter seems to work for me. I could not do the former as I don't have that profile handy.

IM 6.6.0-0 Q16 Mac OSX Tiger

If you have a CMYK profile, then you can use that before your sRGB profile and avoid using -colorspace RGB

see http://www.imagemagick.org/Usage/formats/#profiles

[Moonshine]

Thanks for the reply! I'm testing with 6.6.0-0 Q16 under Fedora core 11.

With your first suggestion I got:

Code: Select all

[root@lightning imagemagick]# convert -colorspace RGB test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' -profile sRGB.icc test-rgb.jpg
convert: color profile operates on another colorspace `icc' @ error/profile.c/ProfileImage/1090.

However it did produce an image that is "closer" to correct:



The second suggestions produced no error and it looks to have the same output:



Levels are looking much better but the color shift is still there.

I actually was using a CYMK profile in addition to the final sRGB profile until I started researching things earlier. That link you gave stated:

WARNING:
If the original image already contains a profile, for example a CMYK profile, then given two profile conversions is a bad idea.

As my sample has a CMYK profile already embedded, I pulled it. Do my examples above match what you see?

Thanks again..

[fmw42]

yes my result also show a pink face. but the cmyk profile should not be pulled out even if in the image, if IM cannot read or recognize that it is there (as I understood that page). what happens when you put it back in and remove the -colorspace RGB?

(Note, I am no expert on -profiles)

[Moonshine]

Adding the CMYK profile back in there at the beginning seemed to give me the same output as if it wasn't included. At least with this image, which has a CMYK SWOP profile embedded. Basically:

Code: Select all

convert -profile USWebCoatedSWOP.icc  test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' -profile sRGB.icc test-rgb.jpg

Results in:



BUT...... I kept fiddling with things and it appears that the order of the profile arguments with respect to other arguments is now important in 6.6:

Code: Select all

convert test-cmyk.jpg -profile USWebCoatedSWOP.icc -profile sRGB.icc -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' test-rgb.jpg

Results in:



While tossing them in at the end:

Code: Select all

convert test-cmyk.jpg -resize 600x600! -unsharp 0.5x0.4+0.8+0.1 -quality '80' -profile USWebCoatedSWOP.icc -profile sRGB.icc test-rgb.jpg

Gives the poor output I was seeing.

I imagine this will trip some other people up also, but at least now I can go to happy hour... happy.