[pure-silver] Re: Development modifications for higher sharpness

> High accutance developers like Buetlers are=20
> very low energy,

Acutance developers are actually high energy developers that are used in
dilute concentration.

> and then you add potassium iodide to=20
> cause the edge affect to enhance the appearance of=20
> sharpness.
> D Purdy

The potassium iodide is not used to cause the edge effect and need not
be present in an acutance developer.  Indeed the classic Beutler formula
and many other acutance developers do not contain it.  Adjacency effects
are caused by the local exhaustion of developing agents and the
associated build up of bromide ion in certain regions of the negative.
I know that Geoffrey Crawley of the British Journal in 1960 advocated
its addition.  I don't know if he was the first to suggest its use.
However, the inclusion of iodide remains controversial.

Jerry
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