Participating Frequently

Question

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

Forum|Forum|15 years ago
April 21, 2010
7 replies
156358 views

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?

FAQ

Dave Creamer of IDEAS

Community Expert

@Test Screen Name asked a reasonable question--how would you change the answer? Additive vs subtractive color is a matter of physics--even Adobe can't change that.

Instead, you start name calling.

David Creamer: Community Expert (ACI and ACE 1995-2023)

S

Sharingene

Participating Frequently

Hello, I just happened upon this discussion after trying to solve the same issue with a brochure I am sending to UPrint. The initial proof was disappointing to say the least. I have spent the weekend trying to educate myself on color-management--oh my goodness! But your suggestions here have already helped make a difference with the first converted CMYK image I am working on--so THANK YOU!

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?

Also, should I get a profile for the paper I'm using as well? --Although I've read somewhere it's hard to have your monitor replicate paper because monitors are so bright....

Oh, thought I'd add a tip to this discussion which might be sort of a "no-duh--well that's obvious" tip to those of you who are able to answer all these questions, but might help those who are new to all of this... When you're still in RGB but you want to see what colors are going to be "out of gamut" once you've converted to CMYK, click Control+Shift+Y (also found under View> Gamut Warning). It's very handy in knowing where to focus your attention once you've converted to CMYK.

Thanks again for the great info in this forum!

p_taz

Inspiring

So glad that you recognised the need for colour management, we get so many new visitors that come here and think we are all nuts just trying to sell colour management or something and that we just like putting down newbies...

You will use the printer's profile as the destination for your 'export to PDF' routine. If you are not making a PDF, you can use the printer's profile for soft-proofing but it rarely helps unless you have a very special job but even then you will usually get a hard proof anyway which is much better than any screen proof.

S

Sharingene

Participating Frequently

Thanks! I'm definitely a believer that color management is something you need to understand if you want your images to look as good in print as they do on the screen (or almost as good anyway). It sounds like Rick's book is a winner--another reason I'm happy to find this post.

Okay, so I need a little more advice for my brochure... I changed my image to CMYK and made some changes that definitely improved its look. I found making adjustments through a selective color adjustment layer really helped improve the area that was looking dull, and lowering the density slider on the "masks tab" in this layer also helped brighten the image.

Okay so now the really silly question... I saved this CMYK file and then went to look at it in another program (outside of Photoshop) and was surprised by what my converted CMYK image looks like---what was an ocean scene of blues now looks like some kind of strange glowing orange and yellow scene. Uhm... is this what it's supposed to look like!? In Photoshop it looked great in a side-by-side comparison with my original RGB. Originally, when I submitted my PSD file to UPrint in RGB they did the conversion of my file to CMYK, and then uploaded a proof back to me--but like I said--their conversion was less than desirable. So I'm just checking--does CMYK not look like a normal color range outside of Photoshop, or did I make some kind of mistake? Thanks!

C

Colin M

Participant

If you know you'll need to be dealing with CMYK on a regular basis, it's well worth picking up Rick's book, CMYK 2.0. I happened upon it while browsing the stacks at the bookstore and it's a total keeper.

Heck, even if you'll only be dealing with CMYK on an occasional basis, it's probably still worth it.

Unlike a lot of previous tomes about working with four-color, it's both very pragmatic and written from a photographer's perspective.

End unsolicited, uncompensated sales pitch.

P

p_d_f

Participating Frequently

...or make sure there is something of contrasting color in your image - say a bright yellow or orange - and emphasize that as well as the Selective color moves Rick has suggested. Having a contrasting color will make the blue seem bluer than it really is, tricking the limited gamut of press inks into thinking they're more colorful.

A

Anonymous

well said, p_d_f.

What p_d_f is talking about is not really CMYK file prep, but basic color theory. Study the Sistine Chapel, Leonardo, or any of the great Renaissance painters.

A

Anonymous

First, don't waste time comparing the vibrant blue in the RGB file to the converted blue in the CMYK file; it'll just get you depressed. Do your conversion, close the RGB file and work on the CMYK file.

Then, place a color sampler point in the blue area of the image. You'll see that read out in the Info Panel as "#1".

The Info Panel readout will show you the C, M, Y, and K ink values (precentages) of that point in the image.

The most vibrant blue (like a sky blue) in the CMYK color space will be 100% cyan (100C) and about 70% magenta (70M). Any amount of the contaminating colors (in this case, yellow and black) will reduce the vibrancy. Yellow will "dirty" it up, and black will darken it. Of course, a lighter blue will have over-all lower ink percentages. The goal in making blue more vibrant is to reduce the level of the contaminating color(s).

There are many ways to manipulate a color in a CMYK file.

An easy way is to add a Selective Color adjustment layer which allows you to add or subtract ink from a specific color.

Open the Selective Color panel.

Click on the Colors pop-up and choose Blues.

At the bottom of the panel, click the Absolute radio button.

While looking at the #1 readout on the Info Panel, use the sliders to reduce the contaminating color(s).

You should see the effect change on screen in real time.

Note: you'll not remove ALL of the contaminating colors; the goal is to reduce them.

This is the VERY short version of what can be a VERY long story. But it should get you started.

HTH,

Rick

_________________________________

Rick McCleary

author, CMYK 2.0: A Cooperative Workflow for Photographers, Designers, and Printers

Peachpit Press

W

Wade_Zimmerman1

Inspiring

You can make it a bit better using again the adjustment layers

and selection Hue/Saturation where yo can concentrate on the saturation and color shift

without worrying about contrast and brightness.

No matter how adjust it do not expect to see this same result on the printed piece it will be duller.

A

Anonymous

Wade_Zimmerman wrote:
You can make it a bit better using again the adjustment layers
and selection Hue/Saturation where yo can concentrate on the saturation and color shift
without worrying about contrast and brightness.

... or use a Selective Color adjustment layer with blend mode set to Color.

The short story gets longer!

_________________________________

Rick McCleary

author, CMYK 2.0: A Cooperative Workflow for Photographers, Designers, and Printers

Peachpit Press

Tom_Murray_1

Inspiring

Try various adjustment layers. Use the mask to isolate the effects.

Now using Affinity Photo

TwitchOSXAuthor

Participating Frequently

The adjustment layers option helped a little. Thanks.

c.pfaffenbichler

Community Expert

If there is a chance that an image will be reproduced in various CMYK-spaces (say, printed as a poster on a sheet fed press but also in magazines or newspapers) it might be beneficial to maintain the RGB-file and color correct there (with the proper View – Proof Setup/s), then separate from that file according to the various requirements.

Correcting the resulting CMYK-files may naturally still improve the results, though.

As you seem not very familiar with CMYK there’s still the question if the CMYK-profile you use for separating is actually the appropriate one for the specific purpose. If in doubt better ask the print-service-provider.

A

Anonymous

Simple. Don't convert to CMYK and it won't look dull.

CMYK has a smaller color gamut than RGB. Google for "cmyk rgb gamut" for TMI.

M

mnorman2007

Participant

It depends on what the end use is. If it is for print, you will never match the RGB (totally different gamut). Using Pantone matching system, we at least have a final target. Your monitor colors will look brighter ssince viewed in RGB but the final printed copy will be acceptable if you educate your customer on expectations.

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