Best time to convert to CMYK

[bluskool]

I was just wondering what everyone here thought about the best time to convert to cmyk in photoshop. Do you guys, when working with an original RGB image, correct for color and tone first (using view proof colors) then convert or convert and then correct for color and tone? Also, do you prefer to sharpen before or after the conversion?


Dan R.

 

[disbellj]

Re: Best time to convert to CMYK

If your Photoshop stuff is going into Quark for output, then you need to convert to CMYK (e.g. 300dpi), grayscale (e.g. 300dpi), or bitmap (e.g. 1200dpi, e.g. a black and white logo) before placing in Quark. This is an early-binding workflow.

For an all-Adobe workflow, then you can leave as RGB and place that into Adobe if you want conversion done on or after output (Note: done during output if output postscript, done after output in rip if export PDF 1.4 or higher out of Adobe and the rip can handle that PDF). However, sharpening will not happen in the late-binding workflow (unless the rip does it). This is a late-binding workflow.

In either scenario, it's best to do any color correction to the RGB using soft-proofing in Photoshop (use CMYK or grayscale profile, use Relative Colorimetric Intent, Black Point Compensation or not depending on what looks best I suppose, and check Simulate paper and ink).

If sharpening is done, it's traditionally after the RGB has been converted to CMYK I believe.

Don

 

[kabel]

Re: Best time to convert to CMYK

Typical workflow for us is to take the raw digital file and open it as a 16 bit RGB file. 1) Apply any needed retouching, 2) adjust levels, 3) convert to cmyk, 4) adjust Curves, 5) convert to 8 bit.

Only if I see a drastic change in the image when it converts to cmyk will I revert to RGB, view the RGB file with Proof Colors on and work with whatever i can to create an acceptable conversion.

We (in-house art department) are too protective of our imagery to let any person or program do the color conversion for us.

 

[kulaysep]

Re: Best time to convert to CMYK

Conversion to CMYK should always be done after the image is manipulated. This will assure that , no matter what you do to the image, it will always conform to thespecifications in Photoshop's color setting.
For example, if the maximum ink limit is set at 250, increasing contrast in cmyk mode will, most probably, cause the ink limit to exceed the maximum specified in the color setting. This will not happen if the adjustments are done in RGB mode.
As a rule, do all major adjustments and manipulation in RGB and then convert to CMYK. After this, you would probably need to do some minor tweaking.

 

[cjwworld]

Re: Best time to convert to CMYK

I agree with Fred.

we do the conversion last. We do the toning in RGB if its to be color.

 

[P-Rex]

Re: Best time to convert to CMYK

It's always better to perform color correcting in RGB, unless you're an expert. You can apply an ICC profile that matches your monitor for more accurate color definition. Here's a resource that covers color correction in detail:

http://www.amazon.com/Exploring-Dig...1563636?ie=UTF8&s=books&qid=1194144963&sr=8-1

 

[cosmo]

Re: Best time to convert to CMYK

Fred is spot on, a good properly converted image in photoshop makes a hell of a difference, especially like he mentioned with ink limits, we set ours to 280%. If its coming from a digital camera, do you tweaking in RGB, then convert to CMYK, make sure you have a good profile setup, you dont want to convert to a uncoated sheet profile if your using coated for example, you will clip the gamut or get unwanted shifts in colour, usually in the dark blues, you can always turn on proof view in photoshop to see the result before you convert, also, the gamut warning will show you the colours you cant reproduce in CMYK.

Edited by: max on Dec 14, 2007 9:07 AM