Color management - CMYK/RGB Values

[yn_justforkicks]

Hi all. I am a budding graphic designer (print and web) and after combing through forums and articles, I have come to a basic understanding of color management. I've often had either web or print work - never both for the same client. For my print work, I usually work directly in CYMK or convert from RGB to CYMK with the profile as per the printer company I work with. So far, so good.

I am now creating a brand identity guide for a non-profit I'm managing.
We need also visuals pretty quickly (print and web).
I created a logo in RGB on PS/Illustrator, converted and saved as CYMK on a separate file.

Color profiles (I work in Europe):

So, as I wanted to take note of the colors in HEX / RGB / CYMK (and Pantone if I can find a relatively close one),
I realized something was off.

I used a green color from another brand identity guide, and their guide says this:

CMYK 80/3/ 100/20 |  RVB 60/ 138/46 | HEX #3C8A2E

My photoshop says this:

When I used the CMYK value from the brand identity guide, it was really far off.

I also used a blue, which I found on Pantone with the following values:

PANTONE 313 -  RGB 0 146 188 | HEX 0092BC | CMYK 100 0 11 2

And on Photoshop, the values are these:

Again, when I used the CYMK values from Pantone, the color was really off from what I wanted.

The "right" colors are the HEX/RGB ones.
Working on a Macbook Pro 2015 (Retina). My monitor is not color-calibrated *yet* (working on it).

FINALLY... here are my questions:

• Right now, my files are on CYMK. Was I wrong to assume that since I was on the right color profile, it would convert the colors properly?
• Where did these other CYMK values come from?
• Which CYMK values do I keep?
• Assuming that the non-photoshop CYMK values are really what they're supposed to be on print, do I need to redo all my files in two different versions (web/print) - one with the RGB values, and one with the CYMK values?
• Is it because my monitor is not color-calibrated? I've done print with this computer, and it's worked pretty well.

Whoever saves my day, a huge thank you in advance!!!

[davescm · Accepted solution]

Hi

The issue is that color values in RGB or CMYK only represent a particular colour when associated with a particular RGB or CMYK colour space - described by the colour profile. The same numbers in different RGB colour spaces represent different colours. There is no generic RGB and there is no generic CMYK - hence there is no generic conversion.

There is no magic about Hex numbers - they are just RGB numbers where the numbers 0-255 are represented in base 16 so give 00 to FF

Examples of RGB color spaces are sRGB, Adobe RGB, ProPhoto........
Examples of CMYK spaces are Coated FOGRA39, Coated FOGRA27 ........etc

If you are working in CMYK then your printer should be able to advise you which profile to choose.

When picking colours from the web , the RGB numbers are often represented in the sRGB workspace. As for the CMYK numbers, if the site does not specify a profile then who knows.

Dave

[yn_justforkicks]

Hi Dave, thanks for your reply. My printer already told me to use Coated FOAGRA39.

So if I understood correctly, the CMYK values depends on the colour space. Can I assume that the CMYK values showing up on my PS as per the CYMK profile i'm on are "correct" and disregard the CMYK values I found on the web?

I've looked at a bunch of brand identity guides like this:

https://www.asitvd.ch/images/content-static/ressources/asit_logo_charte.pdf

(this one happened to match the CYMK values when I put in the RGB values)

Why don't designers specify the color spaces on their identity guides? Doesn't this increase the risk of having the wrong colour printed?

[Test Screen Name]

To be honest, the people who produce colour guides with RGB/CMYK matches and no colour space simply don't understand colour management even slightly. The world is full of people who like making tables of numbers without understanding what the numbers are. It's quite scary.

[davescm]

yn.justforkicks  wrote

Why don't designers specify the color spaces on their identity guides? Doesn't this increase the risk of having the wrong colour printed?

Yes it does - but many don't understand that.

yn.justforkicks  wrote

Can I assume that the CMYK values showing up on my PS as per the CYMK profile i'm on are "correct" and disregard the CMYK values I found on the web?

Yes - particularly if the RGB values are giving you the correct colour. The CMYK values are the RGB numbers converted to your chosen CMYK space (not an unspecified space on the website )

Dave

[D Fosse]

davescm  wrote

As for the CMYK numbers, if the site does not specify a profile then who knows.

...but a pretty good guess is that they will conform to US Web Coated (SWOP) - because they've probably just read numbers off Photoshop, and that just happens to be the default CMYK profile there.

Yes, Dave is absolutely right. Numbers mean absolutely nothing until associated with a specific color space. That's when the numbers get meaningful as a representation of an actual color.

You never know which CMYK profile to use until you have actually talked to the printer. Offset presses are calibrated to different standards around the world, different inks are used, and each profile corresponds to a certain press/paper/ink combination.

In Europe, for coated paper stock, the most common today is ISO Coated v2 300% (ECI). For some reason this is not included in the Photoshop installation and you need to download it from eci.org. Some still use FOGRA39 and some printers will have their own custom profiles.

[sarumbear]

"if the site does not specify a profile then who knows."

COLOR doesn't specify a colour space either. Shall we say "who knows" and keep using it?

[rob day]

I also used a blue, which I found on Pantone with the following values:

PANTONE 313 -  RGB 0 146 188 | HEX 0092BC | CMYK 100 0 11 2

And on Photoshop, the values are these:

It's also worth noting that the Color Picker itself is color managed. If you have no documents open, the appearance and numbers in the picker respond to your current Color Settings setup. If there are documents open the foreground doc's assigned profile affects the picker.

In your capture you are picking a Hex value, which is simply a different RGB notation. The Color Settings' RGB profile will affect the appearance of the specified RGB color, along with the expected CMYK numbers if the RGB color were to be converted into the Color Settings' CMYK space.

So the RGB/Hex values don't change when you choose different RGB profiles, but the color's appearance does. Here's your 0092bc hex value with ProPhoto as the RGB Working space on the left and sRGB on the right:

Any change to either the RGB or CMYK working spaces affects the expected CMYK values, as well as the Color intent and Black Point Compensation settings. The variables that affect the conversion into CMYK are enormous and that's why the web tables are not reliable.

[sarumbear]

"The variables that affect the conversion into CMYK are enormous and that's why the web tables are not reliable."

Does that include COLOR tables as they also do not refer to a profile?

[D Fosse]

Inasmuch as any numbers are given. Any numbers without reference to a color space are undefined.

[sarumbear]

Doesn't this fact makes Adobe Color a toy?

[D Fosse]

Yes! It does indeed, and there was just the other day another thread where we all reached that conclusion. The thing is useless.

[sarumbear]

Thank you for confirming my thoughts. BTW, I chat closed a chat with Adobe. They do not even know it existed and they do not support it. It is for all practical reasons, a toy then.