Hi there
So I'm making a pixel art game and I like the idea of having lights and normal maps but I don't want perfect dark to be pitch black. I'd like to have more control over which color is the darkest. But if I design my sprites with a dark purple where I want to be its darkest, lights will lighten up this tone making it look pretty terrible.

So the way I see it I have two options.
Option 1: make my sprites with black where I want to be always dark then during the game I apply some filter to the entire frame to tweak the colors and adjust the darkest tone.
Option 2: Make a shader that looks for a specific predetermined color (a dark purple on my sprite for example) and keep these pixels from being affected by lights.
I'm sure there are more options though. I'd like to know your thoughts on it. I have no idea how to make shaders either.