On Wed, 31 Mar 2004, Ryuji Suzuki wrote:
> There are a lot more factors described in literature.
>
> Active hydroquinone reduces or eliminates adjacency effect. D-19 is
> often used with or without dilution where adjacency effect is
> undesirable, because its high hydroquinone content practically
> eliminates the effect. The reason is that development reaction product
> of hydroquinone (or pyrogallol or catechol, for this matter)
> effectively enhances the development of the adjacent area. These
> products quickly react with sulfite ion, but when this happens, it
> increases the alkalinity of the solution nearby, again enhancing the
> development. For adjacency effect, you want the opposite effect -- the
> development reaction products to be effective development inhibitors
> and development reaction should release protons.
Another reason why you can't trust "the literature" -- I found that in the
literature also. But my own processing, with extra hydroquinone ADDED to
the developer gave better adjacency effect.
Judy
Received on Wed Mar 31 18:37:57 2004
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