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I have a JPEG image.

On my Mac, when I type:

identify -verbose img.jpg

I get Colorspace: sRGB.

On my Linux box, when I type the same thing I get Colorspace: RGB.

Why? Has anyone encountered this before?

The reason this matters:

I get wildly different results when I use convert img.jpg -colorspace sRGB out.jpg between Mac and Linux. Obviously if they identify the source colorspace differently, then I could see why.

chowey
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1 Answers1

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Ensure both systems are running the latest version. See release announcement about color management.

Color management has changed significantly between ImageMagick version 6.7.5-5 and 6.8.0-3 in order to better conform to color and grayscale standards.

In short

ImageMagick supports color profiles, however, for images without a profile or a declaration of colorspace, ImageMagick assumes non-linear sRGB. Most image processing algorithms assume a linear colorspace, therefore it might be prudent to convert to linear color or remove the gamma function before certain image processing algorithms are applied.

emcconville
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    Thanks, I upgraded and sure enough it works. For anyone else in my shoes using CentOS, you can upgrade to the latest ImageMagick with `yum --enablerepo=remi install ImageMagick-last`. – chowey Jan 06 '16 at 19:19
  • how to make imagemagick show "Uncalibrated" or "Unknown" instead of sRGB in this case? – Greg Sep 29 '17 at 16:58