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Developing the Photographic Negative 1948 US Navy Training Film MN-5383; Fundamentals of Photography
🕑 Added 2020-08-12 20:37:42 +0000 UTCmore at http://quickfound.net/
Originally a public domain film from the US Navy, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://en.wikipedia.org/wiki/Photographic_processing
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.
All processes based upon the gelatin-silver process are similar, regardless of the film or paper's manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films. Kodachrome required Kodak's proprietary K-14 process. Kodachrome film production ceased in 2009, and K-14 processing is no longer available as of December 30, 2010. Ilfochrome materials use the dye destruction process...
All photographic processing use a series of chemical baths. Processing, especially the development stages, requires very close control of temperature, agitation and time.
Black and white negative processing
The film may be soaked in water to swell the gelatin layer, facilitating the action of the subsequent chemical treatments.
The developer converts the latent image to macroscopic particles of metallic silver.
A stop bath, typically a dilute solution of acetic acid or citric acid, halts the action of the developer. A rinse with clean water may be substituted.
The fixer makes the image permanent and light-resistant by dissolving remaining silver halide. A common fixer is hypo, specifically ammonium thiosulfate.
Washing in clean water removes any remaining fixer. Residual fixer can corrode the silver image, leading to discolouration, staining and fading.
The washing time can be reduced and the fixer more completely removed if a hypo clearing agent is used after the fixer.
Film may be rinsed in a dilute solution of a non-ionic wetting agent to assist uniform drying, which eliminates drying marks caused by hard water. (In very hard water areas, a pre-rinse in distilled water may be required – otherwise the final rinse wetting agent can cause residual ionic calcium on the film to drop out of solution, causing spotting on the negative.)
Film is then dried in a dust-free environment, cut and placed into protective sleeves.
Once the film is processed, it is then referred to as a negative.
The negative may now be printed; the negative is placed in an enlarger and projected onto a sheet of photographic paper. Many different techniques can be used during the enlargement process. Two examples of enlargement techniques are dodging and burning.
Alternatively (or as well), the negative may be scanned for digital printing or web viewing after adjustment, retouching, and/or manipulation...
