Bow Tremolo Stamina
While bow tremolos on the strings create a great shimmering or a very climactic effect, make sure to not write too long passages in tremolo. Especially on loud dynamics, this technique becomes quite exhausting and eventually the muscles of your players will become sore which will result in worse playing.
So make sure to not overuse that technique and if possible give your players a little rest after an extensive tremolo passage.
I believe it was well used in noir films, I’m currently working on one, any tips for what to do after a tremolo passage?
It’s not possible to answer a question like “What to do after a tremolo passage?” Tremolo is merely a playing technique that even in itself can create a lot of different colours depending on how you use it. The musical context should be the basis of any consideration of how to continue from there, not the playing technique.