I did most of my film experimentation in the past decade or so with
subminiature formats (Minox 8x11mm) becaust these tiny format
negatives show effects of processing much more clearly than working
with something even as large as 35mm, in comparative terms.
Lots of experiments and precise control of process shows conclusively
that agitation speeds the development of dense areas and contributes
to grain growth/clumping. Leaving negatives sit in "still" developer
with minimal agitation tends to slow development in dense areas (the
active agents become exhausted locally, allowing development action
to continue in areas with lesser exposure), and grain clumping slows
quite a bit.
My process for excellent Minox negatives with APX25 was to expose at
EI 50, process in XTOL 1:1 at 74F and use the time from Kodak's data
sheet plus 15%. Agitation is limited to 5 seconds at start, with a
sharp rap to dislodge bubbles, and then *one* tip of the development
tank by 20 degrees every two minutes, that tip taking 5 seconds. VERY
minimal agitation like this nets about 10-20% tighter grain (eyeball
estimate).
Godfrey
On Dec 14, 2005, at 3:05 PM, Don Sanderson wrote:
I'm aware that aggressive agitation increases contrast
substantially but have never heard/considered/noticed
it having a pronounced effect on grain size.
Could you elaborate a bit on this?
and use minimal agitation to
reduce grain growth.
