Archived posting to the Leica Users Group, 2000/02/28

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Subject: Re: [Leica] Agitation - especially for Mark Rabiner and Stephen Holloway!
From: "Dan Post" <dpost@triad.rr.com>
Date: Mon, 28 Feb 2000 18:05:31 -0500

John-
I was wondering what developer you use. I have had cases where when using a
particularly strong undiluted developer, the 'pumping' of the developer
through the sprocket holes left overdeveloped 'streaks' on the edges.
If this is not the case, then there is a possibility that for some reason,
the agitation is not moving the solution evenly.
I preclude this by leaving a 'head space' in the tank- I don't fill it
completely. If there is no bubble of air at the top- when you turn it over
to agitate- the inertia carries the developer around without really mixing
it up! With a bubble of air in the tank, when you invert- the air goes to
the bottom of the tank, and in doing so- it stirs up the solution!
Some people recommend a one minute water soak- this causes the emulsion to
absorb the non-reactive water, and keeps the process from starting too soon
with short developing times- the water retards the action of the developer
by simply being there until the tank is full and you start agitation, where
it diffuses out.
Possibly your agitation is TOO gentle; try leaving a void in the top of the
tank so that stuff gets mixed better.
Dan