RA-4 process
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RA-4 is
More specifically, common color photographic paper is carefully exposed to form a latent image of the picture, and then the paper is run through the series of chemicals that together comprise the RA-4 process to convert the latent image into the final print. RA-4 uses Color Developing Agent 3,[1] in combination with color couplers in the emulsion to generate color dyes.
RA-4 is a standardized
The actual chemical process occurs at 100 degrees F. The steps: 1. The paper (glossy or matte) is taken through color developer; 2. Bleach/fixer bath; 3. Stabilizer bath which both stabilizes the paper and washes out the chemicals; 4. Drying. Since the paper is Resin Coated, it dries flat and even.
This processing can be done in a machine, e.g. in a minilab, where rotary tubes transport the film through the baths, or by the photo hobbyist in a darkroom setting, using trays for each bath.
Current manufacturers of RA-4 Chemistry include Kodak, Freestyle, Rollei, Unicolor and Tetenal as of 2017.
The result of RA-4 processing is a Type C, or chromogenic print.
References
- ^ "Safety data sheet" (PDF). www.adox.de. Adox. Retrieved 10 January 2020.
External links
- Process RA-4 Publication: Z-130 - Official Kodak lab manual