metallic negative silver image formed in the first developer has no part in the reaction of this step. As the color development progresses, a metallic positive silver image is formed and the color developing agent is oxidized. Oxidized color developer molecules react with the color couplers and color dyes are formed in each of the three layers of the film. Each layer of the film contains different color couplers, which react with the same oxidized developer molecules but form different color dyes. Variation in color developer pH causes color shifts on the green-magenta axis with Kodak E100G & E100GX and Fujichrome films and on the yellow-blue axis with older Ektachrome films. Pre-bleach bath: 2:00 @. This bath was previously called "conditioner", but was renamed pre-bleach in the mid-1990s to reflect the removal of formaldehyde from the process used in the final rinse. In this solution, formaldehyde acts as a dye preservative and EDTA is used to "kick off" the bleach. The pre-bleach bath relies on carry-over of the color developer to function properly, therefore there is no wash step between the color developer and pre-bleach baths. Bleach bath: 6:00 @. This is a process-to-completion step, and relies on carry-over of pre-bleach to initiate the bleach. The bleach converts metallic silver into silver bromide, which is converted to soluble silver compounds by the fixer. During bleaching, iron (III) EDTA is converted to iron (II) EDTA (Fe3+ EDTA + Ag + Br−→ Fe2+ EDTA + AgBr) before fixing. Kodak also has a process variant which uses a higher concentration of bleach and a 4:00 bath time; but with process volumes declining, this variant has become uneconomical. Wash step (optional): Rinses off the bleach and extends the life of the fixer bath. This wash step is recommended for rotary tube, sink line and other low volume processing. Fixer bath: 4:00 @. This is a process-to-completion step. Second fixer stage (optional): Using fresh fixer. The archival properties of film and paper are greatly improved using a second fixing stage in a reverse cascade. Many C-41RA (rapid access) minilab processors also use 2 stage reverse cascade fixing for faster throughput. Final wash: 4:00 @. Final rinse: 1:00 @. Up until the mid-1990s, the final rinse was called a stabilizer bath, since it contained formaldehyde. Currently, the final rinse uses a surfactant, and miconazole, an anti-fungal agent. Drying: Drying in a dust-free environment. See also Replenishment