Converting from RGB to CMYK makes the image dull. How do I fix?

Question

I have an image that has a really bright vibrant blue in it. When I convert it from RGB to CMYK, it gets pretty dull. Is there a "trick" or something to do to a file after converting to CMYK to bring back some of it's vibrancy?

Answer 1

Sharingene wrote:
Question on workflow... so do I convert my sRGB to CMYK, work to fix different color issues using some of the methods above, then what?  Where does the printer's profile come into play during all of this?  UPrint told me for offset printing they use US Web-coated SWOP v.2.  Just not sure what to do with this information
Whenever you convert, you're always converting from the source color space to the destination color space.
In this case, your source color space is sRGB, because that's the color space your file is in.
Your printer told you that the CMYK profile they use is USWebCoatedSWOPv2, so that's the destination color space you want to convert to. You can consider that the printer's profile.
So, how to convert?
There are two ways.
First, you could go to Image > Mode > CMYK. Easy, but maybe not right.
That method will convert to whatever defaults are set in Photoshop's Color Settings (Edit > Color Settings). Check out your Color Settings. If they are set to any of the North America presets, you're in good shape, because the CMYK default is USWebCoatedSWOPv2. However, let's say that the printer told you to use Web Coated SWOP 2006 Grade 3. Then you need to take a different approach...
Second way: go to Edit > Convert to Profile...
In the dialog that appears, click on the Destination pop-up and scroll to find the appropriate profile.
Click OK. Conversion done.
This is a more deliberate method that also gives you control over Rendering Intent. (That's another discussion. For now, use Relative.)
-I guess it's used in soft proofing but sure how all this works.  If I soft proof and it's still not looking right, am I able to edit with their profile turned on some how?
A soft proof is an on-screen simulation of what your color will look like once you do the conversion. In your case, you would turn on soft-proof (command-Y) while still in sRGB to simulate the look of the CMYK color space.
To select the color space to simulate, go to View > Proof Setup.
Click on Custom...
Click on the Device to Simulate popup.
Scroll to find the destination color space.
Then when you hit command-Y, you'll see a soft proof of that color space.
Best practices suggest that you do the bulk of your color correction while still in RGB, but with soft proof on.
Also, should I get a profile for the paper I'm  using as well?
That's what the printer's profile is.
Although I've read somewhere it's hard to have your monitor replicate paper because monitors are so bright....
Not exactly. The challenge in getting a visual match between monitor and proof/print is based on the fact that a monitor is emissive (i.e., it's a light source) and a print is reflective (i.e., it only reflects light that's hitting it.) However, in a proper, well controlled editing environment, it's possible to get a shockingly close match between monitor and proof/print. All the variables are controllable.
The bottom line with all of this is to be able to get accurate, predictable color on press (or out of your inkjet) based on what you see on screen. It can be done; I do it every day. It just takes some study and rigorous process control.
I humbly suggest that you check out my book.
Good luck!
HTH,
Rick
Rick McCleary
author, CMYK 2.0: A Cooperative Workflow for Photographers, Designers, and Printers
Peachpit Press