Recommended Math Composite Node Blend Mode for using brightness and color of one clip for another clip

Greetings, I’m replacing a glass window which has reflections of the room and lights visible in it, and I’m using a nighttime cityscape clip as a roto replacement in the Math Composite node. I was wondering what Blend Mode/s in the Math Comp node would be recommended to incorporate only the color tones and bright/dark lighting of the original window clip onto the cityscape background, without actually incorporating the hard objects reflected in the window? Also, how does hooking into the foreground or background inputs change the result of Math Composite? Please let me know if there might be other nodes to incorporate into the composite to achieve something close to what I’m trying to do. Thanks for any help or recommendations on this :slightly_smiling_face::pray:t3:

Normally, I would use Screen to add in reflections.

Great thanks for the input, I’ll give that a shot.