Recenly i bought some colored gels and tested them in studio
The results was much better than i expected
in the first two photos i had a 3light setup with the gels on the modifier or in the modifier
at the key light
2 speddlights on the back pointing the models head with no midifiers on them
and an 120cm octa above models head facing down
at the next 3 photos my assistand was holding the gels near the models face
in front of a harsh light source, (just a single strobe using honey comb grid)
you can also see the gels in the photos