Photosensitivity[ edit ] Although photographic processes have been in development since the mids, there were no suitable theoretical explanations until with the publication of a paper by R.
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MERGE exists and is an alternate of. Some of the earliest used silver salts that darkened on exposure to light. These salts were coated on metal plates and then had an image projected on them through a lens.
Once the image was created by exposure to light, the image was made permanent by exposing the plate to mercury vapor which probably formed an amalgam with the sliver in the lighter areas that stuck to the plates.
After development, the plates were washed with a hot salt solution which removed the silver from the darker areas where the mercury had interacted less with the silver. More modern black and white photography uses grains of silver halides suspended in a gel.
The chemistry of exposure is typically something like: The developer under the same conditions does not significantly affect the unexposed grains.
Silver halide developers include: Once the exposed image has been developed to the desired degree, it is necessary to halt the chemical process quickly to prevent over-development and the production of fog. The solution used to that end is referred to as the "stop" bath.
Since developers function a relatively high pH's, the typical stop bath is simply a solution of acetic or some other weak acid. The action of the acid is so rapid it usually requires only seconds for the process to be effectively halted.
The silver halides are only slightly soluble in water; therefore, to remove the material remaining after development it is necessary to convert it to soluble complexes which can he removed by washing. Sodium thiosulfate, commonly termed "hypo," has been used for this purpose since The reactions in fixing can be written as follows:Several different chemical processes have been used in photography.
Some of the earliest used silver salts that darkened on exposure to light. Oct 14, · Best Answer: There are two basic chemical reactions which are going on.
1. The developing agent, a reducing agent, reduces the exposed silver halide crystals (AgCl, AgBr, AgI) to silver metal. (by the way, since the developer is the reducing agent, it is being plombier-nemours.com: Resolved. Apr 30, · The chemical wet process involves the film developer, the stop bath (water can be used in lieu of a stop bath), the fixer (also known as hypo), and a water rinse (+ an optional wetting agent to keep the film from developing water streaks when drying).Status: Resolved.
Chlorine chemistry plays a role in traditional film photography in the form of the light-sensitive compound, silver chloride, AgCl. What's in a name? The chemical symbol for silver is Ag, short for the Latin word for this element--argentum.
The Chemical Equation of the Development of Film in Photography.
words. 3 pages. An Analysis of the Big Bang Theory Explaining How the Universe Began. 1, words.
2 pages. An Analysis of the Fundamentals of Television and Television Signals. 3, words. 5 pages. Silver bromide (AgBr), a soft, pale-yellow, water-insoluble salt well known giving an overall equation of: AgBr → Ag + FRACTION Br 2 Latent image formation and photography.
During film development the latent image is intensified by addition of a chemical.