This information is to help guide in choosing the best containers to store photochemicals, to reduce oxidation as much as possible, for improved storage life. For color chemicals, the main interest is with developers. Values are for oxygen transmission rate, units are in nmol*m-1*s-1, at 23 deg C and 0% relative humidity, per https://repositorio-aberto.up.pt/bitstream/10216/88820/2/25962.pdf Low density polyethylene (LDPE): 500-700 High density polyethylene (HDPE): 200-400 Polyethylene terephthalate (PET): 6-8 Ethylene-vinyl alcohol (EVOH): 0.03 - 0.12 PE is used for traditional brown photochemical jugs. PET is used for beverage bottles. EVOH is used for food packaging, including some wine storage "bag-in-box" systems.