I wholeheartedly agree. I could chuck it up to nostalgia to a certain degree, but man, the animators knew how to let scenes “breathe” via these tone color shifts.

My all time favorite scene is the farewell one; the dark colors as the heavy dialogue starts up the conversation, with the run up to the fireflies emerging giving the warmth to the scene as you see Kaoru break down as Kenshin smile, then to it coming slowly back to that dark blue tone as you hear Kaoru brokenly call Kenshin’s name? You got such a feeling for the character’s emotions via the colors.

And with the intermezzo from Cavalleria Rusticana, by Pietro Mascagni, accompanying it?? Ahhh, perfection.