Hello people!

I've been stuck in the world of Corel Painter for the past years and even though i love and use krita alot these days I always find myself returning to painter because of one reason. Namely because of my favourite brush that I have not been able to replicate using the Krita brush engine.

My main problem is that I cannot figure out how to simulate painter's "Resaturation" dynamic.

Resaturation technically is pretty close to Krita's "Color smudge" brush mode, except instead of fading to opacity-zero after reaching a specified stroke-length then the Color brush mode actually kicks in.

Think of it as an brush loaded with a dab of oil that comes in contact with existing wet Oil on the canvas.
First the Canvas' oil-color will get dragged/smudged a bit until it thins out and the Color that the brush is loaded with starts being transferred to the canvas.

Second problem is that I would like to have the possibility to chose "Random" to affect an dynamic just like today it's possible to choose "Pressure" or "Tilt"
I really love being able to get a bit of jitter in the "Hue"-dimension when i block things out.

Anyways here's the brush-specs I've been trying to convert:

Always opacity 100% ( no dynamics )
Size affected by Pressure: Pressure(0.0 -> 1.0) = Size(24% -> 100%)
Resaturation 19% , affected by pressure, e.g. The harder i press the more of my selected color gets transferred instead of smudging around existing colors.
Brush-tip: image
In painter the brush-mode is set to "rendered" which works quite complexly different, but I managed to simulate this in Krita by setting rotation of the brush-tip to follow the stroke.

Yeah that's more or less the main characteristics, here's a sample showing off the brush:


And a small sample of the brush in action:

( It's only my oil brush used in this sample, single layer )

Please help!!

So noone knows if resaturation is supported in krita?
Maybe someone could just point me in the right direction for porting my brush?

Point 1: Resaturation
When you are talking about the difference between blending and adding color, does that translate to the Smudge Length and Color Rate in Krita? If you set Color Rate to your pen pressure, you can add more color as you press harder. The quick examples of 'resaturation' I saw with Painter all had to do with painting over photography, so I couldn't get a good feel for what was going on technically. The Painter examples seemed like a combination of a color smudge brush that constantly samples a layer underneath it.

Point 2: Random property on setting
In Krita, it sounds like you want the Strength property to be dynamic. Right now, you either can make it static, or use a pen technology to determine the Strength like Pressure or Rotation. I don't believe there is a way to have a random strength right now for settings in Krita.

Hope that get us closer to a solution.

Thank you for your reply!

I will look into those properties again, couple of days back when i last tried, i think I somehow got the impression that color smudge and color add were exclusive modes, thus i could only achieve one or the other. I'll look into it again.

You're right on track with your observation, once upon a time I've implemented the resaturation effect in another piece of software, my formula looked something like this:

Code: Select all

dst_color = sample_canvas_area_avreage(x,y) * min(1-distance_traveled*resaturation_strength,0) + brush_color * max(distance_traveled*resaturation_strength,1)

Where 'distance_traveled' in my case, was actually just number painted brush-blobs that incremented during stylus-down, e.g. my resaturation strength did not work as intended with variable brush-spacing.

but then again i haven't looked at krita's brushengine, so not really sure if it makes sense.

Basically, the longer the brush-stroke the less smudgy i'd like it to be and just paint the color from the color-selector. thanks!

Ok I've experimented some more! And i know now what's been bugging me.

The formula i wrote before is wrong, instead of constantly sampling the area underneath the brush It should only be sampled once!

e.g.

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dst_color = sampled_color_at_stylus_down * min(1-distance_traveled*resaturation_strength,0) + brush_color * max(distance_traveled*resaturation_strength,1)

So I think i accidentally solved my problem..

Attaching screenshot:


The key was to disable "Smudge Length" and "Smudge Radius", And only have "Color Rate" active.
In that panel I had to check the strength to be affected by distance, and most importantly Invert the curve into a downhill, and finally uncheck "repeat" checkbox. ..

Thanks alot for helping me realize what i was looking for, and pointing me in the right direction!

Great to hear you figured it out. The brush editor in Krita is really powerful, but it also can be confusing if you don't understand how it is structured and what settings work with other settings.