In a recent thread the subject of adjacency effects was discussed. I
have some further questions about that I wonder if any of you might
like to address.
The literature on this subject appears somewhat contradictory.
Richard Henry notes that since the creation of adjacency effects is
via lateral diffusion the type of agitation should in principle not
matter, and he observes that he obtained adjacency effects with very
vigorous and constant agitation. Yet he notes that research quoted by
Todd reached different conclusions on the importance of agitation.
Also, some sources suggest that only metol based developers give
adjacency effects since phenidone is highly resistant to the
restraining action of bromide. And on this list Ryuji mentioned that
the development by products of certain reducers (he mentioned
hydroquinone, catechol and pyrogallol as I recall) reduce or
eliminate adjacency effects.
In spite of any of the above I have been able to get very extreme
adjacency effects with Pyrocat-HD and minimal agitation procedures,
and I do not get them with constant agitation. And I believe Judy
mentioned that she was able to get adjacency effects using
hydroquinone.
I would welcome further comments on these issue from Ryuji or any
others on the list who may wish to comment. Also, if there is any
recent literature relevant to the subject it would be nice to have
the source.
Sandy King
Received on Fri Apr 9 08:43:23 2004
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