Hi, I'm trying to adapt Krita to write math formulas just like Khan Academy, as I already asked here https://forum.kde.org/viewtopic.php?f=139&t=131468. Another problem I have is that I need to fastly select colors, and I need these colors to be exactly the same always, not some color that looks like the older one, so my formulas stay the same color. I don't want to use the color picker enabled when I touch my pen or the mouse middle button. Instead, I want to be able to select colors by numbers. Is it possible? 1 = blue, 2 = red, 3 = ...

Thanks!

You can use the pop-up palette, which is on right-click and has the color history in it, and there's also a coor history on H, which can be configured via the advanced color selector options.

Some little note about color picker - it can be fast enabled by holding "Ctrl" key in brush mode, I found experience quite comfortable and fluid (much more comfortable, than switching tool explicitly by GUI buttons or P/B hotkeys)