Here's the general outline of developing B&W with the BTZS tubes. There are
two parts to the tube, the tube and the cap. The cap holds the 2 ounces of
solution. Place the solution in the cap and turn out the lights. Roll your
4X5 neg into a tubular shape and slide into the tube. Screw the tube into
the cap. I normally process two tubes at a time for ease in agitation. Now
you can turn the lights on. Shake the tube for a while and drop into a tray
of water at the temperature of your developer. Put your fingers on the
outsides of the two tubes and flip them together, creating a log-rolling
action. Every minute swap the placement of the tubes, thus reversing the
rolling of the tubes. After the development time is complete, turn on only
the safelight. Remove the cap and trash the developer. Drop the tubes into
a tray of stop bath and do the log-rolling. Finally, remove the negs from
the tube and drop into a tray of fix. Turn on the lights and finish.
I have done E6 with the tubes, though it's a bit tougher, as there are more
processing steps to go through and developing at 102 degrees F is touchier.
Also, as the developer solution is reused, you'll need containers to dump it
in. I would look to develop at lower than normal temperatures to make
things a little easier. I haven't done too much E6 in the tubes, but it's
doable and, if you don't have an affordable lab to go to or the money to
kick in for a Jobo, a blessing.
The tubes cost about $18 each for the 4X5 size - there's an 8X10 size also.
You can fabricate your own materials to do the same thing, but I thought for
$40 the convenience was well worth it.
george