Professional films should be kept in a fridge. When these films leave the factory, they are ready to use. Amature films are not. They need to age for a while untill they are at their best. Heat helps (most of the times) a chemical process. So, amature films can be stored at roomtemp. Pro-films need to be kept at a low temp to avoid the chemical process to run out and killing the film.(posted 9323 days ago)