Daylight Processing Tank for
Large Format
This works like a Nikkor Tank, only it holds
4 8x10 hangers, or 4 up 4x5. It is made from 1/4" ABS and standard
plumbing fittings. It is sized to hold a little less than 1 gal., to allow
for waste. Five hangers are loaded in the dark, the lid is fixed in place and the
rest of the process is done in daylight.
There is an internal baffle that allows the solutions to fill from the bottom. An escape valve on the top speeds up the fill and dump steps so that no pre-soak is needed.
With agitation every 30 sec., the result is actually better than standard tank processing.
More Details:
Details of air vent
Inside of Cover
To assure a water-tight seal, the inside of the cover is lined with a piece of soft Neoprene. Note that the vent hole is offset to create a light-trap.
Detail of Internal Baffle
This shows the internal baffle which allows
the chemicals to fill from the bottom. The inside tank dimensions are
10.5"deep x 10.375" wide x 1.800" thick.
Tension Adjustment
The loop devices that seat the cover need
to have the proper tension to prevent leaks. They are made from
stainless steel threaded rod which are screwed into a small bar at the bottom.
When the nylon nut at the top is threaded back onto one of the halves, they
are free to be adjusted, as shown.
Rapid Pour
One inch PVC fittings are used to assure rapid filling and dumping.
Top Edge of Tank
A sharp edge is needed to assure a good seal.
Typical Edge Detail
A three sided groove cut close to the edge makes assembly much easier.