Converting / ICC SRGB

[denice]

When I convert the Mode from RGB to CMYK,
the main change I see in any images is in the
Blue uniforms, they really lose saturation in the
Blue.
When I set my icc profile to SRGB, and change
the mode to CMYK, the image becomes an "Untagged CMYK"
image, is this correct?

Thank you for any help


Denice
Mac OSX, Running Classic for Quark 4.1. System G4.

 

[blueark]

An untagged CMYK image is just an ordinary CMYK image. In other words, it uses whatever default color profile your version of Photoshop is set up for. A tagged CMYK image has it's own color profile embedded in the image, usually to fit into a specific color management workflow. In other words, unless you've got specific workflow requirements, don't worry about it.

As for the loss of saturation, that's perfectly normal, and most noticable in blues and greens (the human eye is less sensitive about variations in reds). It stems from the fact that RGB mode has a wider color gamut than CMYK, ie. it can display a wider range of colors. Therefore, the conversion process has to compromise with certain colors.

One piece of advice is to use View > Gamut Warning, or View > Proof Colors while still in RGB mode. Gamut Warning will block out any RGB colors that can't be shown in CMYK, and Proof Colors will give you a CMYK preview. You can then adjust your colors before commiting to CMYK mode, giving you more control over how much you want to compromise.