RA-4 process
Encyclopedia
RA-4 is Kodak
's proprietary name for the chemical process most commonly used to make color photographic prints. It is used for both digital printers of the types most common today in photo labs and drug stores, and for prints made with older-type optical enlargers and manual processing. 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, the colors of which are dyes in the paper.
RA-4 is a standardized chromogenic
process used worldwide to make prints with a variety of equipment, photographic paper, and chemicals. Kodak created the RA-4 process for its color negative photographic papers. Fuji
, Agfa
, and other present and past photographic supply companies also make or have made both papers that are compatible with the Kodak chemicals, and chemicals that are compatible with the Kodak papers. These other companies typically call their equivalent processes by other names, but to most photographers, RA-4 is used as a generic term.
The result of RA-4 processing is a Type C print
.
Eastman Kodak
Eastman Kodak Company is a multinational imaging and photographic equipment, materials and services company headquarted in Rochester, New York, United States. It was founded by George Eastman in 1892....
's proprietary name for the chemical process most commonly used to make color photographic prints. It is used for both digital printers of the types most common today in photo labs and drug stores, and for prints made with older-type optical enlargers and manual processing. More specifically, common color photographic paper is carefully exposed to form a latent image
Latent image
A latent image on photographic film is an invisible image produced by the exposure of the film to light. When the film is developed, the area that was exposed darkens and forms a visible 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, the colors of which are dyes in the paper.
RA-4 is a standardized chromogenic
Chromogenic
Chromogenic refers to color photographic processes in which a traditional silver image is first formed, and then later replaced with a colored dye image.- Description :...
process used worldwide to make prints with a variety of equipment, photographic paper, and chemicals. Kodak created the RA-4 process for its color negative photographic papers. Fuji
Fujifilm
is a multinational photography and imaging company headquartered in Tokyo, Japan.Fujifilm's principal activities are the development, production, sale and servicing of color photographic film, digital cameras, photofinishing equipment, color paper, photofinishing chemicals, medical imaging...
, Agfa
Agfa-Gevaert
Agfa-Gevaert N.V. is a European multinational corporation that develops, manufactures, and distributes analogue and digital imaging products and systems, as well as IT solutions. The company has three divisions. Agfa Graphics offers integrated prepress and industrial inkjet systems to the...
, and other present and past photographic supply companies also make or have made both papers that are compatible with the Kodak chemicals, and chemicals that are compatible with the Kodak papers. These other companies typically call their equivalent processes by other names, but to most photographers, RA-4 is used as a generic term.
The result of RA-4 processing is a Type C print
Type C print
Chromogenic color prints are full-color photographic prints made using chromogenic materials and processes. These prints may be produced from an original which is a color negative, slide, or digital image. The chromogenic print process, was nearly synonymous with the 20th century color snapshot...
.
External links
- Process RA-4 Publication: Z-130 - Official Kodak lab manual