Gradient Map - colors are not consistent

[SilvRO]

Hello,

I have a CMYK document (ISO Coated v2 300%) with an illustration only in 100% black. I want to use the Gradient Map adjustment layer to add 40% cyan in the darkest areas (0% in white).

The problem is that with the color c40, m0, y0, y100 the color is converted to 100% black. If I put c40, m0, y0, y99 it "works".

Another big problem: as soon as I want to edit the black color, the values of the gradient map are modified although the result remains unchanged.

GradientMap_Issue.afdesign

[Wosven]

I would use the channel mixer for this or a gradient map from 40% cyan to white in multiply mode.

 

GradientMap_Issue2.afdesign

[Wosven]

That's completely crazy: if I apply a gradient from C40-B100, it doesn't seems to add the cyan.

If I close it and modify the gradient layer, once opened the C40-100B is transformed to CMYK black.

If after modifying the values to C40-B100, and test using the right-click menu, it's again set to CMYK black, but all the screen is white, I can't see anymore the drawing, only the artboard name at the center in small!

[Wosven]

There were bugs in AP with adjustement layers, seems that's not completely solved.

[SilvRO]

Absolutely. I use the Channel Mixer to work around the problem (more elegant). I posted this topic to report what seems to me to be a bug.

But thank you very much for proposing these solutions 😄

[Sean P]

Hi SilvRO,

Thanks for the file and for letting us know. I think the issue here is that the Adjustment is just working in an RGB colour space - this is why values are getting changed as they're being converted to RGB. And when 100%K is applied I think it is acting as though it is RGB0,0,0 so not having any effect.

I will pass it along to development! 
Thanks,

[hannah]

Hello dear people, does ANYONE please know a WORKAROUND here?

My work requires me know to recouler a greyscale-image (black should be a specific cmyk colour, white should also become a specific colour, like a bright beige). I tryed to reach this via channel mixer but i cannot make it work...

 

Dearest people of affinity, i so hope that this will be solved. It complicates but sometimes, like right now, makes my work impossible.

This problem persists across all affinity products (desktop photo, designer and publisher). (Connected to it, there seems to be an issue presenting any cmyk colour truthfully within the context-menu of the gradient map tool, like along the little gradient bar.).

 

THANK YOU

 

[Wosven]

2 work around in the second post of this thread.

[Wosven]

1 hour ago, hannah said:

like a bright beige

Can you give a Pantone reference for this colour?

[hannah]

Thank you for replying.

I haven't searched for corresponding Pantone colours yet, but I could try, if using spot-colours during the process would yield better results?!?

But ultimately it'll be printed in CMYK, and the final product has to "match" what the client already has... I came up with the aesthetics for the client using adobe products and now i cannot reproduce this "simple" effect with affinity.

Attached is screenshot of what i try to achieve. I need the same colours to be available within the picture as well as in simply colored areas...

 

 

 

[hannah]

Ah, sorry Wosven, I just saw your hint. Yes, I tried with channel-mixer but can't work it out for the beige at the same time. And no layer-effect is giving me what I want neither.

[Wosven]

It's more complex than it looks (part of the text like "telefon" and "studio" seems darker, and there are triangular and more yellower part in the second one too)…

I didn't find any Pantone matching those colours, and it's difficult without to be sure of the result.

Using fill layer seems simpler than trying with a colour mixer layer. Gradient Map give the worst result again.

1784195381.afpub

 

1784195381_ScreenShot_v2.afphoto

1784195381low.pdf

[Wosven]

The bug keeps on occurring with CMYK files....

I create a gradien with some greys... once opened again, it's blue-green !

Th app should memorize CMYK colours, since it's impossible to revert back to the same exact colour from RGB.

 

 

[SilvRO]

On 4/22/2020 at 9:25 AM, Sean P said:

Hi SilvRO,

Thanks for the file and for letting us know. I think the issue here is that the Adjustment is just working in an RGB colour space - this is why values are getting changed as they're being converted to RGB. And when 100%K is applied I think it is acting as though it is RGB0,0,0 so not having any effect.

I will pass it along to development! 
Thanks,

Hello Sean,

Still no news on a possible correction of this bug?

For simple cases, we have an efficient method to get around it. On the other hand, for gradients with more than two points, it's very complicated.