Trichrome photography is an old technique used to create color photographs using black and white film. Three photographs are taken, one each with a red, green and blue filter.
Traditionally these 3 exposures would then be projected through the correct colored filter on top of one another to view them but now in the modern day we have the luxury of
aligning and combining the images digitally.

Taken on Fomapan 400 with an EOS-1, 70-200 f/2.8L and developed in Rodinal