Photo : Color editing, lost quality tweaking CMYK compared to tweaking RVB

[Ken Lecoq]

Hello everybody !

First, LOVE to the Affinity team and the software because it's great ! 

The question that I have is about color editing in affinity photo "photo persona".

I'm working a lot on color tweaking now to get some great emotional and powerfull results !

I really love using the channel mixer adjustment to change colors, and mostly toutching the CMYK, because you can change the colors on the picture kind of individually. On the other side, when you are tweaking colors using the mixer adjustment layer with RVB, all the colors of the picture are moving when you toutch to a color. You have more flexibility tweaking CMYK. 

But, problem ! I noticed that when I was tweaking the CMYK channel, the quality of the colors inside the image was quite bad compared to the same image tweaking the RVB channel... And some quite bad artifacts are appearing, in the shadows areas mostly. 

Is it normal ? Is there any way to tweak the CMYK channel without having this bad color artifacts ? Is the color format of the picture is changing from RVB 16 bits to CYMK 8 bits when I apply this layer ?

What is the best way to do a really nice and creative color editing without loosing so much quality ? 

Thanks a lot, I really hope somebody is able to respond to this question.

Ken. 

 

 

 

 

 

[Ken Lecoq]

UP ! I edited the topic so it was easier to understand, and clear pic examples, the CMYK edit looks awful compared to the RGB edit... 

 

[Gabe]

Hi @Ken Lecoq,

Welcome to the forums. 

The first cause would be the limited CMYK gamut. CMYK covers a lot less colour information than RGB. 

#

The next one would be your workflow. You have a 32bit/RGBA document, and you make adjustments on CMYK 8 bit. 

You would have to either work on RBG or CMYK from start to finish, or you will have artefacts. 

Thanks,

Gabe. 

[Ken Lecoq]

Thanks a lot @GabrielM

Well, I Guess I'll stay with SRGB or Adobe RGB as the gammut is wider !

I kind of found a good way to tweak cyan yellow and magenta staying un SRGB, using Hue ajustement, I can tweak yellow, cyan, magenta, tes, green and blue individually, changing thé saturation and the luminance of each colors, and it's staying in SRGB because even tweaking CMYK this way, I don't have thé bad artifacts ! 

Ken.