P3D RE: From Bob Porter: Home Brew E6

["Greg Tank" <tanker@xxxxxxxxxxxx>]

>So for fun, I'm going to try E6 at home to see if I can do a better
>(or worse) job.  I ordered Tetenal chemistry yesterday (for use in
>a JOBO CPE-2 rotary processor).  Looks pretty straightforward with
>1 to 4 rolls (or so) done at once for about half an hour (and $1-2
>chemistry cost per roll of film).

>Anyway, any others try this themselves?  Did it make things better
>or worse?

I have done considerable processing at home including the old transparency
process which had a light reversal. In all my photo engineering classes they
drilled these four variables into your head:
TIME
TEMPERATURE
AGITATION
CHEMICAL STRENGTH

Any variance of any of these from the ideal will contribute to inconsistent
results. Now Black and white processing has a fairly large window for each
of these variables but Color is another story. With color you must be very
systematic, precise, and consistent - just like a mechanical film
processors.
1. Chemical Strength - Mix exactly as the package states be clean - Consider
distilled water to remove water as variability.
2..Temperature - Processing temperature must be within the tolerances as
stated. With color this can be plus or minus 1/4 to 1/2 degree. A machine
does this well, at home is a challenge. Must use a photo thermometer
accurate to within plus or minus 1/4 degrees. Use a stainless steel
processing tank - (transfers temperature well) and use a water bath to set
the processing canister in during processing inactivity to minimize
temperature variability. Water bath should be maintained at the exact
processing temperature specified. Too high of a temperature will accelerate
the chemical reaction. To low of a temperature will retard the chemical
process. Temperature of the developer must be like baby bear porridge
"Juuuuuust right"
3. Agitation - "Consistently random" As the film develops the chemistry next
to the film is changed due to development by products. Agitation removes the
spent developer from the surface and replaces it with fresh. Too much
agitation will cause development to be accelerated for the scheduled time.
Too little agitation will cause underdevelopment for scheduled time. There
as many agitation techniques as photographers, but the wrist rolling method
is fairly standard. Find a method that you think can perform "Consistently"
but moves the chemistry around the film in a "Random" way as not to develop
streaking or chemical marks due to poor agitation. (Sounds like you have a
mechanical processor so this should make processing repeatable.)
4. Time - The length of time for development. Normal or Push processing.

With these four variables Temperature is going to be the challenge and most
difficult to control. Once you have a good agitation process and stick with
it  is not a variable. Time is straight forward, Chemical strength is easy
to obtain if you are precise, cleanly, and trust the recipe.

Hope this helps, It can be done and results can be consistant if all
variables are understood and minimized.
Tanker

      Gregory A. Tank
"tanker@xxxxxxxxxxxx"