CYMK black is not true black

[zpires]

This has been posted as an issue on Windows for years. I'm just adding that this is a bug found on the Mac version as well as late as 1.10.4. I'm attaching a recording of a document with a CYMK color profile. Dragging on any of the color pickers to the bottom does not select a pure black, even when the color panels show RGB colors. It is the CYMK document color profile that causes the issue.

The most problematic instance of this issue is with mask layers because the color panel defaults to show Grayscale colors. Dragging to get a "black" color does not actually select black. It's not obvious immediately, as it would be if the CYMK color sliders were shown.

This problem has apparently existed for years. Do we have any kind of plan for release for a fix for this?

I don't think this should affect any fix that may have been added, but just in case it does I'm on macOS Mojave 10.14.6.

 

[Old Bruce]

I am not seeing this. Are you sure the brush you have is at 100% opacity and flow and is a brush that is not transparent in any amount?

[j.king]

Not sure if this is the exact same issue you reference but I've noticed in Affinity on both mac and windows that the K in CMYK does not appear solid black. If I want to see a good solid black I drag all sliders to 100. Sliding only K to 100 looks more like a very dark and slightly brownish gray. Sorry to hijack with a possibly different topic.

[Alfred]

10 hours ago, j.king said:

Not sure if this is the exact same issue you reference but I've noticed in Affinity on both mac and windows that the K in CMYK does not appear solid black. If I want to see a good solid black I drag all sliders to 100. Sliding only K to 100 looks more like a very dark and slightly brownish gray. Sorry to hijack with a possibly different topic.

What you’ve described is kind of the opposite way around from the issue that the OP is trying to deal with. CMYK black should be K 100 only; K 100 mixed with C, M, and Y is ‘rich’ black.

CMYK with all sliders set to 100 is ‘registration’ black, used for registration marks so that the four printing plates can be correctly aligned. Total Area Coverage (TAC) is usually restricted to 300 or less so that the paper doesn’t get saturated with ink, which means that if the value for K is 100 the values for C, M, and Y are each going to be between 30 and 60 or thereabouts.

[zpires]

11 hours ago, Old Bruce said:

I am not seeing this. Are you sure the brush you have is at 100% opacity and flow and is a brush that is not transparent in any amount?

100%. Using a basic brush. I just changed the size with the ] button.

 

[stokerg]

11 hours ago, zpires said:

100%. Using a basic brush. I just changed the size with the ] button.

 

Thanks @zpires, i've been able to replicate the issue on my Mac and will update the report for this issue we already have logged for Windows.

[zpires]

On 11/16/2021 at 10:14 PM, zpires said:

I'm attaching a recording of a document with a CYMK color profile

i guess also a forum bug. why is my original video changed? that's just wacky. here's what i originally attached.

 

[Patrick Connor]

19 hours ago, zpires said:

i guess also a forum bug. why is my original video changed? that's just wacky. here's what i originally attached.

 

Sorry that was my fault trying to fix a forum issue with Chrome. I think I have mended your first post now. Sorry again

[Bassthang]

Has this bug been fixed yet? I'm using Photo on Windows. I didn't notice that the "black" background on my image wasn't true black until I dropped it into a web site, which has a true black background. The "black" of the image is much lighter.
The Info tool shows CMYK as 70%, 67%, 66%, 79%.
Image format is RGB/8.
I've turned off all other layers and the black layer is normal, 100% opacity.

[Old Bruce]

3 minutes ago, Bassthang said:

Has this bug been fixed yet? I'm using Photo on Windows. I didn't notice that the "black" background on my image wasn't true black until I dropped it into a web site, which has a true black background. The "black" of the image is much lighter.
The Info tool shows CMYK as 70%, 67%, 66%, 79%.
Image format is RGB/8.
I've turned off all other layers and the black layer is normal, 100% opacity.

Simple answer is don't use CMYK for RGB images. Use RGB colour panel for RGB colours in RGB Documents. Use CMYK colour panel for CMYK colours in CMYK documents. Otherwise on conversion from CMYK to RGB you'll get odd/wrong colours.

[Bassthang]

No, not so simple. . . nothing to do with the colour formatting at all. I'm not that green!
But I'm kicking myself now. . .

It was giving 23/23/23/255 in RGBA on Info.
I couldn't seem to stop this from being the case. If I went back and checked the RGB sliders in Swatches, they showed as all zero, but a flood fill still gave me 23/23/23/255 in RGBA on Info.

I tried out a new image from scratch. One layer, RGBA format. Black fill. I double-clicked the black in the swatches, and checked that the RGB sliders were all at zero. The CMYK readings given in the swatch tool were 72%, 68%, 67%, 88%. However a flood fill gives all zeroes in the info. So it had to be something in this file.

Then I spotted the REAL problem: there was a 3D FX applied to the black layer. No idea when that happened (I'd used it on some of the other layers), but there was a bevel that was just about visible, but partly masked by some ruler lines I'd placed on the image. Turn off the FX and I get proper 0/0/0 black.
Doh!

[Old Bruce]

10 minutes ago, Bassthang said:

Then I spotted the REAL problem: there was a 3D FX applied to the black layer. No idea when that happened (I'd used it on some of the other layers), but there was a bevel that was just about visible, but partly masked by some ruler lines I'd placed on the image. Turn off the FX and I get proper 0/0/0 black.

Good catch and thanks for reporting back with the solution. I have been bitten by other "D'oh" bugs of mine own creation.