Bug 492146

Summary:	Some colors do not exist for blending
Product:	[Applications] krita	Reporter:	Norsq <helloumbreon.shiny09>
Component:	* Unknown	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	halla
Priority:	NOR
Version First Reported In:	5.2.3
Target Milestone:	---
Platform:	Compiled Sources
OS:	Microsoft Windows
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	idk if you can see it but it's the two greys im talking about Screenshot of the canvas + layer thumbnail sorry for bad explanation. the video attached is of me showing the colors not blending meanwhile on other colors they do blend

Description Norsq 2024-08-24 21:20:39 UTC

Created attachment 172915 [details]
idk if you can see it but it's the two greys im talking about

***
If you're not sure this is actually a bug, instead post about it at https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***

SUMMARY
Some colors do not exist for blending, if i use a grey and i put a lighter grey even if i blend them with a blending tool, taking it from the wheel a color in between does not exist, if i try to export a photo with the color that should be in between it just makes it one of the two greys instead of the mix. I know this is a problem that only i have as i asked other krita users and they said they could blend the two colors.

STEPS TO REPRODUCE
1. use any brush with a darker color
2. put a lighter color
3. blend them

OBSERVED RESULT
no color in between.

EXPECTED RESULT
a nice blend with all the colors in between.

SOFTWARE/OS VERSIONS
Windows: 10 pro
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
i did try to install krita again but it did not fix

Comment 1 Halla Rempt 2024-08-25 09:42:23 UTC

I'm not exactly sure what you mean, but the file you have attached _is_ strange: the image is rendered as if it is filled with a two-tone gray gradient and differs from the thumbnail.

Comment 2 Halla Rempt 2024-08-25 09:43:18 UTC

Created attachment 172931 [details]
Screenshot of the canvas + layer thumbnail

Comment 3 Norsq 2024-08-25 10:02:46 UTC

Created attachment 172932 [details]
sorry for bad explanation. the video attached is of me showing the colors not blending meanwhile on other colors they do blend

Comment 4 Halla Rempt 2024-08-27 11:56:23 UTC

Hi Norsq!

After some discussion, we figured out what's up. The layer thumbnail is weird because the layer is much bigger than the image. The banding issue is because you're using a linear gamma profile on an 8 bit image. Please check this chapter in the manual for an in-depth explanation: https://docs.krita.org/en/general_concepts/colors/linear_and_gamma.html

Comment 5 wolthera 2024-08-27 12:00:11 UTC

Hi,

I suspect what you're experiencing is what we call "banding" (as in, gradients become bands of color). This is because you're trying to use a linear profile with 8bit color depth, and there's no enough bit depth in 8bits to be able to have a visually smooth gradient. You will need 16bit at minimum to get a smooth greyscale in a linear profile, or convert to an sRGB trc profile.

To do so, go to image -> convert image color space.

There, either choose:
1.  RGBA, 8bit integer/channel, sRGB-elle-v2-srgbtrc.icc
2. _or_ RGBA, 16bit integer/channel, sRGB-elle-v2-g10.icc

1. is the more conventional setup, 2 is a lot heavier on the computer but the gradients tend to mix nicer. See https://docs.krita.org/en/general_concepts/colors/linear_and_gamma.html for details.

If this doesn't fix your issue, we'll need more information on what is going on.