I wonder if they would like to market my new contrast control filters I have developed for black and white photography. They are simply based on the property of existing filters -- a filter lightens its own color and darkens its opposite color. For example a yellow filter lightens yellow and darkens blue.
It is a two filter set. A filter made with specially formulated white coating on a glass lightens the whites of a scene and darkens its opposite -- the blacks. This effectively increases the contrast of the scene. No more boring flat negatives on those gray overcast days! No extra-long boring development times in the darkroom!
The second filter was more difficult to create -- it took a lot of chemistry and some physics. But a breakthrough in electromagnetical fusionality has allowed me to create a black filter that effectively lightens the blacks in the scene while darkening its opposite -- the whites. Finally a way to reduce contrast in those slot canyons and other high contrast situations without having to do complicated compensating development!