RGB TO CMYK

Start here:

http://digitaldog.net/files/CMYKPart1.pdf

http://digitaldog.net/files/CMYKPart2.pdf 

Hi

Conversion from RGB to CMYK is generally moving your image into a smaller colour space. So, in many cases, colour saturation will fall. Maybe that’s what you've noticed?

This is because a print process (ink on paper) does not have the same gamut (range of colour) nor can it produce a black as deep as you see on screen. And of course print processes differ, think Vogue magazine - v -  newsprint.

The different CMYK colourspaces are defined by their ICC profiles and they show different characteristics, so you need to be sure to use the right CMYK profile for the print process your image is destined for.

And before converting, maybe make a copy of the RGB, saving an RGB original as well as the CMYK, just in case - that's future proofing. The CMYK file you make has been somewhat restricted, so its good to keep an original RGB copy for future use.

Wen converting to CMYK I recommend you use the edit / convert to profile dialog because that way you are taking control of the conversion.

You may like to read my blog post on profiles here: color management / colormanagement : about icc colour profiles

and: https://www.colourmanagement.net/advice/press/

Photoshop has a useful ability to softproof (view/softproof/custom/ choose CMYK profile) this predicts the changes that you should expect after conversion to CMYK.

It helps accuracy here if you check the box for ink black, additionally - sometimes checking paper white also helps although that can  often make paper white a strange shade due to brighteners in the characterised paper (in the ICC profile).

Ink black may make tour image appear a touch less dense in blacks than actual print, so there are limitations to the accuracy of a softproof, however it is a very useful tool.

I hope this helps

if so, please do mark my reply as "helpful" and if you're OK now, please mark it as "correct" below, so others who have similar issues can see the solution

thanks

neil barstow, colourmanagement