One of the best features of my Mamiya film camera is the option to swap film backs. It allows me to switch films mid-roll. One time it backfired because I wasn't paying attention. I arrived at this farm in north-central Washington in 2013 with three film backs. I blasted through my first roll, which I thought was monochrome. I had attached a red filter to darken the sky. Guess what? It was a color roll. I discovered my error when I picked up my developed film. The images look like scenes from the apocalypse (below). I returned to the farm in 2014 with multiple film backs. No operator error this time (example above).