Have a look at dry plate and wet plate photography. Dry plate is silver and gelatin on a glass plate. https://unblinkingeye.com/AAPG/DPlate/dplate.html https:/

Have a look at dry plate and wet plate photography. Dry plate is silver and gelatin on a glass plate. https://unblinkingeye.com/AAPG/DPlate/dplate.html https://unblinkingeye.com/AAPG/DPlate/dplate.html The primary difference to film is that the glass substrate is replaced with cellulose acetate. https://en.wikipedia.org/wiki/Cellulose_acetate https://en.wikipedia.org/wiki/Cellulose_acetate