My name is Marius Hanzak, and I’m an experimental photography student currently studying at the Cleveland College of Art and Design in the UK. For one of my recent projects, titled RGB Church Street, I experimented with making color photos using black and white film.
The method I used is essentially how color film works, which has a separate layer of emulsion sensitive to each color. This just separates the colors across three negatives using color separation filters.
The filters are Red 25, Green 58 and Blue 47B.
Each image requires 3 exposures on black and white film. One shot with a red filter, letting only red light through, one shot with a green filter, letting only green light through and one shot with a blue filter, letting only blue light through.
In the darkroom, three enlargers were set up — one for each color. Making the tricolor prints involved tracing the projection of the first enlarger with a pencil onto paper, then using that sketch to the align the easels of the other two enlargers.
The filters were used with their corresponding negative under the enlarger lenses and exposed onto the paper. Adjusting the individual times for the red, green and blue exposures was all it took to get the colors right on the final prints.
This could be achieved using a single enlarger by exposing one color and then putting the paper away while you set up and align the next color. It can also be done digitally by scanning in the negatives and combining in Photoshop.