By What is Negative (Photography)
Have you ever click a photo through a camera? Not with the digital one but through Negative.
My dad was a photographer. He used to click photos through the negative camera. The photo was printed through Negative. A Negative is an image, usually on a strip or sheet of transparent plastic film, in which the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest.
The chemical used in photography is then Developer and Fixer. The print shop used developer, stop bath, and fixer in its photographic production process. The exposed film is placed in the developer solution, which changes silver ions on the film into black metallic silver. This creates the film image. A stop bath is used to halt the developing process to prevent the picture from getting darker. Fixer then makes the image permanent and light-resistant by dissolving any remaining silver halide salts.
1. Developer
Developer solutions and powders are often highly alkaline and are moderate to highly toxic. They are also sources of the most common health problems in photography; skin disorders and allergies. Developers are skin and eye irritants and many are strong allergic sensitizers. Some common ingredients in developers are hydroquinone and sodium sulfite.
Hydroquinone can cause de-pigmentation and an eye injury after five or more years of repeated exposure, it is also a mutagen.
Sodium sulfite decomposes to produce sulfur dioxide (a toxic gas) when heated or allowed to stand for a long time in water or acid.
2. Fixer
Fixer contains sodium thiosulfate, sodium sulfite and sodium bisulfite. It may also contain potassium aluminum sulfate as a hardener and boric acid as a buffer. Fixer solutions slowly release sulfur dioxide gas as they age. However, when these solutions are contaminated with acid from the stop bath, the gas sulfur dioxide is released at a more rapid rate.
Sodium sulfite decomposes to produce sulfur dioxide when heated or allowed to stand for a long time in water or acid.
Sodium thiosulfate upon heating or a long-standing solution can also decompose to form highly toxic sulfur dioxide gas. Many asthmatics are particularly sensitive to sulfur dioxide.
Sodium bisulfite also decomposes to form sulfur dioxide if it makes contact with boric acid or acetic acid.
Boric acid is moderately toxic unless there is an exposed wound on the skin, then it can be highly toxic.
Negative should be sink to Developer and Fixer consecutively in order to create a shape that was captured.
My dad used to make a cylinder shape of paper. The candle is needed to be burning inside the cylinder in order to print photos by capturing shapes of Negative to the paper. Then the paper should be sink to Developer and Fixer consecutively. In this way, negative photos are printed.
Hope you got a little idea about how Negatives are processed.
Photo by Markus Spiske from Pexels
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