If you are interested about Krita, may I also recommend checking out MyPaint? The two programs are similar but very different also, I routinely use them both.

If you are interested about Krita, may I also recommend checking out MyPaint? The two programs are similar but very different also, I routinely use them both. What I like about Krita is that it's very powerful, its interface has a lot of stuff going on (not a bad thing, it's very easy to understand and use) and it's definitely the better digital painting application out of the two. What I think works better in MyPaint is sketching and quick notes/drawing. It has the concept of infinite canvas where you can keep drawing and drawing and drawing. I also prefer its preset brushes over Krita's, but that's just personal preference. My normal workflow is, if I want to draw some painting with definite proportions and size and everything, I use Krita. If I just want to sketch something or jot down some notes, I use MyPaint. My last infinite canvas with MyPaint ended up being over 200MB of png with a very ridiculous resolution because I kept writing and writing and zooming and zooming all my notes and I didn't notice how big it actually became (I use it as a big whiteboard for sketching my projects).