> >
> >
> John,
>
> Are the 11X14 and 16X20 sheet film drums you refer to above made by
> Jobo? And what is the physical configuration that allows the develper to
> flow around the back of the negative? How are the these tanks different
> from the 8X10.
>
> I have seen at leat a 100% increase in time with carbon, and much more
> with even slight over development.
> \
> Sandy King
>
The big tanks are drums, but have a holder in them that holds one piece
of film. This is hard to describe, but it is a sheet of what looks like
thick polyethylene, larger than the film, with raised "bumps" around
where the edge of the film would be. Each bump has a button in the
center of it. The edge of the film is held between the button and the
bump giving space between the base of the film and the sheet. The sheet
comes out of the drum to load, and with the agitation of the machine,
the solutions flow behind as well as on the face of the film.
The 8X10 tanks are just tanks and the film is curled into a small
cylinder (the tank has 5) and so the back of the film is pressed against
the wall of the tank.
Gordon Huthchins (sp?) , developer of the PMK formula uses two volumes of
developer in succession to combat the aerial oxidation caused by the
machines agitation.
John