photoshop, but im switching back to firealpaca since adobe changed their licensing stuff. its like if bic was allowed to flip through and use your sketchbooks because you used their pen.
if you wanna know my technique, i dont use straight black for my lines, and colours are an overlay layer. put them both into a folder set as "normal" instead of pass through. multiply layer for the shadows ect. this is so that the colours dont get jacked on the background but still influence the lines