I saw the ghost bride hey arnold fanart timelapse and how were you able to know that the "blueish" colors felt right? (its right when you put the base flat colors then added like a "blue filter" to the colors, around 1:42). I color picked the colors and its crazy, helgas "skincolor" is actually a blueish gray but beside all the other colors it looks like her skincolor.
I've seen it in many cases when they put a character in a different backgrounds so they gotta match the characters colors to not feel out of place, but I have no idea how to do that.
(the timelapse in question)
honestly i just eyeballed it, it doesn't have to be the right color at first because you can always adjust as you go along. note that this grayish blue layer i put on top of the base colors ended up looking warmer once i added the rim lighting, which was a more saturated blue.
as i added more warm elements to the background (aka purple and magenta) that initial blue shading layer had to be adjusted to match. you may notice the shadows on helga ended up being more greenish than blue. that's because it's the complementary color to magenta, meaning they're on opposite ends of the color wheel. between those two sits blue-teal, which i used for the lighting. i think those are three of four colors making up a tetradic palette? the remaining one would be orange, which i didn't use.
that's the walkthrough for that specific piece but let's talk a bit more about how to pick colors for shading, lighting and backgrounds:
i didn't touch on values because that's a bit trickier, it depends on not just the color but also the material you're coloring (a soft wool sweater isn't gonna have the same contrasting values between lights and shadows as, say, a shiny leather jacket.)
i hope this made sense? these aren't hard rules, obviously you can go crazy with colors in art if you so choose. sometimes you have to bend the rules to get the desired effect.
