Just in case people are wondering about the EN title TL:
Silver halide
銀塩
It's not ginshio, it's ginen.
Film photography is a big part of this manga.
Silver halides are light-sensitive chemicals, and are commonly used in photographic film and paper.
Silver halide is a salt.
Hence the name "A Sprinkling of Silver Salt"
It's actually a pretty clever wordplay from Wakadori-sensei, tbh fam.