HSL Saturation Modelling - Wet Brushes and around

[americogobbo]

I'm working on the wet brushes set. They are very interesting to use but I am not capable to resolve the relationship between with the grey values and HSL saturation instances... always the greys are changing the Hue... they appear redish... Perhaps is not possible to do it.
With other colors works fine my problem is only to modelling de grey tones.
In this model I'm using basically the Opacity and Color HSL saturation.
Some suggestion?
http://pastebin.com/Y7wJjY84 (brush)

[iirelu]

Screenshots of what it looks like?

[americogobbo]

The problem is only with the greys... white works well. Perhaps some detail on my brush model.

[0ion9]

@americogobbo :

"The problem is only with the greys... white works well."

That sounds like a bug. The problem should also occur with white and black. It's a problem that is inherent in the HSL model: A color with no saturation (ie. a pure grey) has no real hue, so an arbitrary hue value (usually 0, which is red) is used whenever converting from RGB.
I think we work with HSL as much as possible inside the brush engine to avoid hitting this type of problem, but it seems that there is some codepath where we end up converting to RGB and back then storing the new color (with hue value of 0) in the brush HSL info.

[americogobbo]

Ok, I understood. Can I help to clarify this problem with some task?

[achadwick]

I see it now. Affects "Change color satur. (HSV)" and "Change color satur. (HSL)".

This is a brush engine issue I guess. Closed in favour of mypaint/libmypaint#15.