CMYK: color picker - imputs for CMYK colors

[MichalSZZ]

For inputs fields like in RGB or HSB. All in 0-100%.
It helps when you have to set color as a CMYK in the project

[photopea]

I dont know if anyone actually uses these CMYK values in Photoshop.

BTW. did you know, that in Photoshop, setting RGB of 0,0,0 results into CMYK =75, 68, 67, 90
And CMYK = 0,0,0,0 is RGB =34, 31, 32 ?

[TheRadicalDreamer]

I was about to recommend the same feature @MichalSZZ XD

I am also had to add that the eyedropper shows the CMYK color code (or replace the sRGB when i have the mode activated)

To be honest, after reading Ivan's comment i could not tell why i would like to see this particular feature.

But photoshop does have it:

And after i though it about a moment it is because when i am working from scratch. I cannot pick a color then use it.

I have to "guess" it when using CMYK mode

For example, i would like certain shade of green for my CMYK project, but when i go to the color picker, i see all the gamut from sRGB, and i have to guess which color i would have after picking.

So photoshop has something called gamut warning, which tells you up until where you can pick colors on the CMYK gamut:

[MichalSZZ]

I work in Illustrator when I have to do something to print but trust me - if someone don't have such a program and have to do for example Bisiness Cards with special UV printing places. The print houses want to have project in PDF and second file with places that shpuld to be printed in UV. Designer sets that UV fills to 100% K for example or 100% magenta.

[MichalSZZ]

I didn't know about that conversion RGB<>CMYK but I think that can be not so easy to understand and can work properly... I am not a DTP specialist. That is super deep topic.

[photopea]

The conversion beteween RGB and CMYK depends on your current color settings, it can be different each time. Usually, people use sRGB for RGB space and US Web Coated v2 for CMYK.

Colors can be described by 3 numbers (RGB, HSB, Lab, ...), but CMYK has 4 numbers (one is redundant). That means, that each color has infinitely many CMYK values, which can represent it. E.g. in Photoshop, if you enter CMYK (0,0,0,100), you get RGB (35,31,32). But if you enter RGB (35,31,32), you get CMYK (70,67,64,74). The colors (70,67,64,74) and (0,0,0,100) are identical in CMYK.

Also, there are colors in CMYK, which do not exist in RGB. So they are replaced by the most similar RGB value.
So you can have two CMYK colors, which have different numbers, and look different when printed, but they have the same RGB value and look identical on your screen.

[TheRadicalDreamer]

So maybe when in CMYK mode, we should have the color picker changed to display CMYK gamut, rather than sRGB one?

[MichalSZZ]

But if you enter RGB (35,31,32), you get CMYK (70,67,64,74). The colors (70,67,64,74) and (0,0,0,100) are identical in CMYK.

When I printed a book - some pages was in Black and White. But I made a mistake and I have only changed the photo to B&W.
That pages was B&W but wasn't look like I want. They was mixed from all CMYK color. Not like in w newspaper, where you have only black paint in printing machine.
When I changed it to real B&W, then I had black and white made only from shades of gray. When I inspected the colors - it was made from only 0-100% of K.

As I said before - I am not a DTP specialist - 99,999% time of my work is for the internet purposes only, but I know that CMYK color mode isn't so easy as only conversion the colors as a numbers.

That is not the example for our main topic above, but my company have a business cards. We have 2 main colors on it. When we are printing them - we use 2 Pantone colors. One for "red" - and that color is made from one paint in the machine (you do not see the dots on print when look closer) and one color is black with shades of that black (you do not see black as a mixed colors from CMYK or something like that).

[photopea]

@MichalSZZ "When I changed it to real B&W" - what do you mean by that? Did you make a change in a PSD in Adobe Photoshop? Did you export a PDF next, or some other format?

Usually, the CMYK values you see in an image editor have absolutely no relation to the ink, which will be used while printing. E.g. if you have only Cyan colors (M,Y,K are zeros), it does not mean that only Cyan will be used when printing. Printers usually have their own inks and color spaces, which rarely correspond to US Web Coated v2.

[MichalSZZ]

@MichalSZZ "When I changed it to real B&W" - what do you mean by that? Did you make a change in a PSD in Adobe Photoshop? Did you export a PDF next, or some other format?

In Photoshop there is a Grayscale mode. I think it was made using that method (I don't remember now - that was 3 or 4 years ago). Then all graphics was imported to InDesign. After all - print house got a PDF file.

Usually, the CMYK values you see in an image editor have absolutely no relation to the ink, which will be used while printing. E.g. if you have only Cyan colors (M,Y,K are zeros), it does not mean that only Cyan will be used when printing. Printers usually have their own inks and color spaces, which rarely correspond to US Web Coated v2.

We are talking about home/office digital printers with ink/toners etc. or about giant printing machines who print in offset?

[TheRadicalDreamer]

Sorry, but i will try to synthesize:

I was wondering if Ivan @photopea could add a warning gamut, like Photoshop does, when you have CYMK mode enabled:

And @MichalSZZ is asking if Ivan @photopea can add a greyscalemode, like Photoshop does:

If you need me to create a separe issue, tell me and i will do

[photopea]

Ok, I have added the "CMYK gammut" checkbox to the bottom of the Color Picker. It will mark the "unprintable colors" with gray.

I think entering CMYK values is too confusing and nobody really does that, so I will not add it to Photopea.

[TheRadicalDreamer]

It's perfect! As you said, nobody will enter numbers, but the gamut warning is perfect. Thank you very very much. Now I can work much better with the printer. Even create stuff from scratch now with the warning ╰(＾3＾)╯ Le mar. 2 nov. 2021 à 09:49, Photopea ***@***.***> a écrit :

…

Ok, I have added the "CMYK gammut" checkbox to the bottom of the Color Picker. It will mark the "unprintable colors" with gray. I think entering CMYK values is too confusing and nobody really does that, so I will not add it to Photopea. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#3883 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC2BFJVJ5DQC66Y5AWUVQVLUJ7M4TANCNFSM5GVYYG5A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.