Despite their small size minilab machines may use chemical processing just like larger dedicated photo processing labs, using processes such as CP-49E or RA-4 for photographic paper processing, and C-41 for film processing. All necessary processing chemicals may arrive in a box (replenishment cartridge) containing enough bleach, developer and fixing agents to be mixed automatically for an estimated amount of paper, eliminating the need to manually handle and mix chemicals.Minilab machines were used in stores to perform film processing and printing on the spot and in a short period of time, usually less than one hour from start of film development to the end of printing, partly because it eliminated the need to send rolls of film and printed photos to and from a large central photo processing lab.