Later, it occurred to me that it might be an interesting way to selectively
hyper specific areas of a sheet of film (was imagining a laminar flow of
nitrogen to be inert, and then a point flow of "sensitizer" (was thinking
anhydrous NH3 at the time) towards the edge of the film from the points
wanting added sensitivity. The hard way to do a graduated ND filter, I'll
admit, but was curious if it would work.