David Nebenzahl wrote:
On 1/23/2004 8:03 PM Jean-David Beyer spake thus:

Randy Stewart wrote:



"Tom Thackrey" wrote in message
om...

On 23-Jan-2004, (Michael Scarpitti)
wrote:

Mechanical agitation that is invarying inevitably will be
harder to control than manual agitation using inversion in a
standard tank. The allure of mechanization is obvious, but I
process exclusively by hand, and never have uneven
development.


Gee and I thought consistancy was the objective. I didn't
realize that varying agitation was part of the creative
process. ;-


Gee Tom, I don't think that agistation methods, apart from some
extremes, have anything to do with "the creative process" either,
but then mechanical drum processing of your film doesn't
guarantee "consistency" which is worth achieving, as this thread
as demonstrated.

Mr. Sccarpitti's style does [not] get very far with me, so I find
it stange to take his side on this point. However the inherent
problems of constant agistation of the type provided by Jobo,


What _are_ the _inherent problems_ of constant agitation? AFAIK,
the only problem is the contrast is higher, and that is completely
controlled by decreasing the development time or increasing the
dilution of the developer.


I'm guessing that the problems associated with constant, invariant
agitation in this device (Jobo) must have something to do with the
interior geometry, topology or hydrology of the gizmo, as I never
have problems with my rotary processor, which is the Beseler Unidrum
(for 4x5 and 9x12). There must be something inside the Jobo--some
baffle or something else in the flow stream--that causes
standing-wave patterns, eddies if you will, that lead to these "road
ruts".


I disagree. If there were an _inherent_ problem to the Jobo processor
(more precisely, its tanks and | or reels), then _everyone_ would get
these problems, and I do not. Many people use them successfully, and
some even use their fancier reel-less tanks for negative processing with
success. I could certainly measure non-uniformities easily enough on
uniformly exposed negatives that I make when performing film
calibrations with my MacBeth TD-901 densitometer that reads to 0.001
density units on the high-sensitivity scale. And _I just do not get
those alleged nonuniformities_. Furthermore, I do not employ heroic
procedures to get this uniformity. I do keep the tank level with a
bubble level, but I am probably being too compulsive about that. I
prewet (B&W anyway), but as a practical matter, I doubt that has
anything to do with it, but I cannot be bothered to omit the pre-wet
because I would have to recalibrate and it is too much trouble.

The _only_ time I got what I might call road ruts was the stripe
parallel to the 5" edge when using the obsolete pre-2509N sheet film
reels. These have been discontinued a decade or two ago. By now, I would
have supposed people would have either upgraded their tanks and reels or
given up rotary negative processing.

It has come to my attention that some people attempt developping
negatives in print (paper) tanks. Maybe there is a problem doing that,
but if you use the wrong tanks, you are on your own.

--
.~. Jean-David Beyer Registered Linux User 85642.
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