Cyan is an open source cross-platform image viewer and converter, designed for prepress (print) work. Like converting an image from RGB to CMYK, or the other way around. Cyan supports color profiles complying with the International Color Consortium (ICC) standard, and strives to create as color-accurate images as possible, with support for RGB, CMYK and GRAY with up to 32-bit image depth.
Cyan should be relatively easy to use and understand. The first thing you should know is that Cyan converts images using color profiles. Converting an image to another colorspace requires two profiles, one with the same colorspace as the image and a second profile with the desired output colorspace.
Cyan requires some minimal setup before usage. You will need to select default color profiles for RGB, CMYK and GRAY. These are used when you load an image without an embedded color profile.
You can set a color profile for your monitor if wanted, this will enable a RGB preview/proof of the final image. Note that this will add a performance penalty and you will need a color calibrated monitor with the color profile (available in Cyan).
For final adjustments you have rendering intent and black point compensation.
Load image and verify the input profile (the embedded is recommended).
Now selected the desired output profile (in this example we want a CMYK image for print).
When you are satisfied with the result just hit save. you can output as JPEG, TIFF and PSD.
Open GIMP and select
Cyan/Import Image, in Cyan open the desired image and convert to RGB, then hit
save and your image is automatically imported into GIMP.
When you are finished editing in GIMP select
Cyan/Export Image, in Cyan convert to CMYK then hit
save, you can save to TIFF, JPEG and PSD.
When Cyan starts it will scan your home folder for GIMP 2.x plug-in folders, if found it will install a Cyan Python plug-in in the folder that does not have it.
If you upgrade GIMP and
Cyan/* is gone just launch Cyan manually once to update the plug-in against your new version of GIMP, this will only happen on GIMP feature releases (2.8=>2.10 etc).