Does the silver become silver metal by the Bromide or develo

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Lowell Huff
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Postby Lowell Huff » Fri Apr 22, 2005 12:16 pm

The silver halide molecule is converted to silver by the exposure to light. the developer then changes the silver to silver oxide(black). The bromide is an anti fog or restrainer.


Ornello
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Re: Does the silver become silver metal by the Bromide or de

Postby Ornello » Thu Jan 19, 2006 6:36 pm

AJIce wrote:I was wondering wheter the electron from the Bromide created silver metal to for the "latent image" or whether the developer created the silver metal.
The decomposition of silver halide into silver and halogen begins with light, and is amplified by the developer.

dfoy
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exposure and latent image

Postby dfoy » Tue Apr 18, 2006 8:33 pm

Silver halides, when chemically reduced, split into a halide ion and a speck of metallic silver. They can be reduced by light, heat, pressure, etc. etc. The speck of silver thus formed is too small to form an image.

What developer does is "amplify" the speck -- in a long series of reactions, the developer takes silver ions out of the surrounding aqueous environment and adds them to the silver speck, forming long filaments of silver, and the mass of filaments thus formed eventually becomes large enough to contribute to image formation. What is formed is a mass of metallic silver, not silver oxide, but the metal is so finely divided that it appears black.

Bromine ions, which are liberated by the reduction of silver bromide (and are also part of the emulsion, and sometimes part of the developer) have a role to play in inhibiting and controlling the rate of reaction, but they do not cause silver to form.


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