Wanted to do coloring and remembered about Krita and the tutorial about flat coloring (Flat Coloring — Krita Manual 5.2.0 documentation) mentioned the Colorize Mask and it’s awesome!

Needed to actually understand it, and even had to watch a video tutorial (Tutorial: Coloring with “Colorize-mask” in Krita - YouTube) but it was so worth it!

It’s basically a bucket fill tool on steroids, and even might be reason enough to move away from Inkscape for some of these tasks!

Cleaned lineart:

Mask (red is transparent):

Result:

Result with random brushes moon texture below it:

Interesting bits:

• any unfilled areas will be filled, that is - if there’s an area that should be left alone it has to be explicitly marked as transparent or any color. This was the most confusing to me at first
• The colorize mask layer should be Multiply, but if there’s anything else below it it’ll be a mess - sometimes it should just be converted to a paint layer w/ the correct settings to see what it will look like in the end
• if you want to remove all instances of a specific color and use color select by color tool for that - it WILL be a mess because borders, and the color mask tool has already a button to remove a color, USE IT.