Controlling color mixing in Painter brushes
- Why do some brushes buildup to black and others not?
- How come if I paint white over a dark or colored background, nothing happens (or I get weird colors)?
These are frequent questions we get, and both can be explained (and fixed) with a very simple change in the brush settings.
Note: This technique can also be very useful for making a brush more friendly for autopainting or cloning (because this will make the brush not buildup to dark/black, which can easily happen when cloning or autopainting)!
In the sample images below, all the brush strokes were created with this variant:
The top-left strokes were created using the default color mixing for this brush. The bottom-right strokes were created with a modified variant of this brush, which uses a different color mixing model.
In this first image, I used the same color for the brush. Notice how the color mixing model used by default goes to black/dark:
In this image, I was using white for my brush color, on a colored background. Notice the colors I am getting instead of white using the default settings for the brush.
In this last image, I am again using white for my brush color. Notice how I am getting nothing using the default settings for the brush.
These 3 images show how using a different color mixing model can have a big impact on the behaviour of the brush.
Changing the color mixing model
Painter allows you to control what type of color mixing you want to use in your brushes. This setting is stored with the brush. As a user you may want to switch the type of color mixing used on a particular brush to get the desired behaviour. You might want to create different versions of the same brush, that switches between color mixing models.
In the examples above, I am using the variant: Pencils - Sharp Colored Pencil. This brush by default uses BUILDUP color mixing. It is also using GRAINY HARD BUILDUP from the Subcategory list to get that nice grainy effect. (These settings are stored in the General brush controls, under Method and Subcategory).
To make the "modified" brush, that uses the different color mixing from the examples above, just switch Buildup to COVER.
To maintain the nice grainy effect, choose GRAINY HARD COVER for the subcategory (since this particular brush was using Grainy Hard Buildup previously).
Save the brush variant if you like it
Why does Buildup behave this way?
Without getting into too much details, Buildup is inspired from subtractive color mixing, which is intended to simulate how dyes, paints and inks mix together.
Here is a link on the topic on wikipedia: subtractive color mixing
The "Buildup" mixing in Painter can be very useful in creating amazing artwork. However, sometimes you just want your brush to paint with the current color without any buildup behavior. This is where the "Cover" color mixing comes handy!