Getting back to the original question, which was building a rack to hold
processing trays in a vertical configuration, not building a sink...
I would be very nervous about sliding trays full of chemicals in and out
during processing. Doing so under a safelight seems to me just asking for
flooding. Even if you do it in a sink, you'll be wasting chemicals.
Better to have the trays fixed during use and offset top-to-bottom as has
been suggested. Developer on top, stop in the middle, and fix on the
bottom is the natural progression and drips from one to the other during
processing pose no risk to the integrity of the chemicals.
The idea of a two-tray stack for toning, with toner on top, is a good
one *provided
you have good ventilation* in your working area. Otherwise you're going to
get a snootful of ammonia (assuming selenium toning) every time you inhale.
Since I have an unventilated micro-darkroom I do my selenium toning in the
kitchen - the process doesn't require darkness. This allows me to spread
things out more, and the bigger space really helps with the odor even if I
don't turn on the vent fan. Since I generally tone in batches separately
from printing sessions, I use four trays - distilled water prewet/presoak
tray, selenium toner tray, (also mixed in distilled water), tap water rinse
tray, and HCA tray. I carry the prints to the print washer my darkroom
after HCA, holding them by a corner over a 5x7 tray to catch the drips;
this is far preferable to trying to carry an 11x14 or 16x20 tray full of
solution! Of course, I always make sure not to do this around food-prep or
meal times.
Steve
