Put a warning in Brush Editor that build up mode is broken

[cgidesign]

I was trying to make a brush in Krita 5.3 on Windows and used Painting Mode “build up”.
Unfortunately I forgot that this mode is broken when painting in a default 8 bit document.
It took me a few hours to remember about the bug.

It would be nice if there would be a warning in the brush editor to not use build up mode if the brush is intended to be used in 8 bit documents.

Better of course would be to fix the brush engine but that might be out of reach because of limited development resources.

Bug report already exists:

502489 – Brush build up mode - issue at low opacity - color never reaches 100%

Forum thread:

Brush build up mode - issue at low opacity values

Tested with Krita 5.2.9, 5.3 alpha and 6.0 alpha (Windows 10) - no pen, only touchpad of the notebook. Brush (pixel engine) is set to “Build up” in the settings (all pressure settings are off). As I understand it, in this mode the “Flow” settings get ignored (they don’t have an effect anymore) and “Opacity” acts like the “Flow” parameter. This mode builds up color in a single stroke if I paint over the same area multiple times (like with a real pencil on paper where you move it forth and back …

[Takiro]

I guess it would be better to fix the bug instead?

[cgidesign]

I would love that, but the first bug report I found was from 2022. Because of that, I don’t think the developers consider it important enough to invest precious time in it. However, a warning would prevent users from spending hours in build-up mode, only to discover that it’s broken.