RGB to CMYK??

[chkphoto]

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I have a publication that is asking for photographs in CMYK color. These images have already been processed in AdobeRGB. When I convert them to CMYK the blacks become dark grays (muddy) and the colors subdue. Do I have to reset levels and saturation after conversion to CMYK or will they publish as they were in AdobeRGB? Or re-process straight to CMYK?

 

Thanks in advance for any advice.

[jaapv]

What I have learnt is that most publications prefer to convert to CMYK themselves, using their own profiles. I would ask them if that is a possibility with them as well. If not, you could try converting to sRGB to narrow the colourspace before converting to CMYK.

[roberts2424]

When it doubt it's always a good idea to call the company printing your work. Ask them what they recommend.

[sdai]

If you don't do pre-press work there's no need to bother with CYMK.

[Jamie Roberts]

So here's what I've learned supplying CMKY to publications and other press types:

• In general, actual press workers don't actually use ICC profiles--they strip them out, so forget about colour management the way you'd manage a print to your lab or to your printer.
  
• However, the magazine probably wants a standard CMYK profile attached from Photoshop. Ask them what they need in terms of the CMYK profile. If they can't tell you, then use one of the defaults from Photoshop if they insist on CMYK.
  
• Jaap is right: I always convert from Adobe RGB or something larger to something smaller first, like ColorMatch or sRGB. Then convert to CMYK. Why? Because CMYK is a small colorspace and is smallest where Adobe RGB is largest (in the cyan areas). The probability of producing something way out of gamut is larger. sRGB is much smaller, and so has less tendency to mess up. Not that PS can't do a good job going directly, but there are times when that gets tricky.
  
• If the magazing seem completely clueless about CMYK, supply an sRGB or ColorMatch file and tell them to convert themselves.
  
• Forget the blacks looking muddy--unless you have a lot of black content that gets just mushed together in CMYK. If that's the case, you can adjust the amount of Gray Compensation and Under Coating in the CMYK set up. It's not exactly for the faint of heart, but you can easily make a lighter black "underimage" if the detail in blacks is important.
  
• If the magazine seems to have a clue about CMYK, you could ask them about ink limits and listen to what they tell you
  
• The most important thing to do: supply them with a printed proof of how the shot should look so that someone on press will have a clue about what it should look like. This assumes the magazine cares enough to pass on the proof
  

[MV8]

Sad but true, your RGB image will not look like your CMYK file. As stated above the color gamut of CMYK is much smaller than that of any RGB space. Usually you would make color corrections in RGB, convert and proof the CMYK file to look at the color but very important is to have your proofing system set up for SWOP (to simulate the presses). SWOP is the standard for printing on web press which is what publications print on. You can check out SWOP.org to get more info and profiles to convert to.

 

MV8

[chkphoto]

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Thanks to all for the informative replies. In my experience, this is the first publication that has asked me for CMYK - and it is a photography journal. I've always just submitted SRGB Tiff files to other publications.

 

I did what was suggested in the replies and converted to CMYK from SRGB. A small tweak to levels and color saturation, but I understand the ever-present difference from transmitted light (computer screen) to reflected light (magazine page) So from here we'll see.

 

Really appreciate all the good input.

 

Thanks