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

[TwitchOSX]

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?

[Guest]

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

[Sharingene]

Hi Rick,

I just posted a second part to my question and then saw your reply.  I really appreciate your taking the time to write such a helpful response, thank you.  I also thought you might be happy to hear that after reading the above entries today, I did go check out your book on Amazon and ordered one.  I'm looking forward to getting it.  I've been reading through a ton of different things on the internet, but am looking forward to having a more comprehensive resource in printed form.

I have learned so much about Photoshop and a myriad of other photography topics in the past year--it's amazing the more you learn, the more you realize how little you know!   Thanks again, I may be asking a few more questions!

[Sharingene]

Hi everyone,

Thank you again for your suggestions!  I really appreciate your taking the time to reply.  I still have a really basic question and want to make sure I'm not doing something wrong.

After working on an image and saving it in CMYK, if I go to look at this saved image in another viewer ie: View NX (Nikon) or IrfanView the colors look very different from the RGB version--sort of day-glow neon.  Is this normal?  The same image looks completely normal in Photoshop.  I am guessing my confusion about this is because there's some basic piece of information I'm missing (like maybe it has something to do with what ViewNX or IrfanView are set up to view).  But I just want to double check I haven't created some kind of monstrosity since it looks so different in these viewers.  I guess I can just send it in and see how the proof comes back, but I'd sure appreciate an education from anyone able to reply!  Thank you.

Oh, one other question!  The images for my brochure were resized considerably from the original.  Is it better to work on the original sized image when making these color conversions and corrections?  Instinct tells me yes.

[Wade_Zimmerman1]

I would say yes as well smart approach.

[Printer_Rick]

Sharingene wrote:

Oh, one other question!  The images for my brochure were resized considerably from the original.  Is it better to work on the original sized image when making these color conversions and corrections?  Instinct tells me yes.

I would color correct in source color at original size, using adj layers and Proof Setup.

If resizing and USM is desired, do that in source color too, but use SO's or copies.

As others have already suggested – do not convert in Photoshop under normal circumstances. Let InDesign or Quark do the conversion to CMYK on output.

[Printer_Rick]

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--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? 

Somebody may have already mentioned, in Proof Setup select the appropriate CMYK profile. If the image is already CMYK select the profile of the image. Then enable "Simulate Paper White."

When you do this the image will look flat and dull. But at least it's a more honest appearance, provided your monitor setup is correct.

Monitor white point color temperature (5000K, 6500K) can affect the display of white points in images too, although in theory it shouldn't. Maybe others can offer some insight on this.

Anyway, the idea behind "Simulate Paper White" for CMYK is pretty neat. The paper white is built into the ICC profile. It is expressed in Lab values.

Under normal circumstances, and for file conversion purposes the paper white cannot be allowed to be a factor. After all – the CMYK can't possibly be brighter than the paper it's going on, right? So in a file conversion, the white is regarded (and should be regarded) as L100 a0 b0.

But in reality the paper does have dullness and a color. To see this, fill a CMYK space with white. Now Convert to Profile. Select Lab. Absolute Colorimetric intent.

The resulting Lab honors the true color of the paper. For US Web that ends up being L89 a0 b4. Dirty and a little yellow. The truth hurts.

This is what's going on with "Simulate Paper White", an absolute colorimetric soft proof conversion. It's a neat trick but a lot of people don't use it because it makes an image look like CRAP.