Assertion: film's grain | /r/HasProperty | based on the size of the grains
Facets:
Source sentences:
text: = 1 – ( 1 – k) light, where light is proportional to the number of photons hitting a unit area of film, k is the probability of a single photon striking a grain (based on the size of the grains and how closely spaced they are), and density is the proportion of grains that have been hit by at least one photon.