I have made about ten different UV units for myself, my workshops and for
others and the designs vary on nearly every occasion given the situation,
my mood, the phase of the moon, the student's needs, etc etc. Bulbs up,
bulbs down, you say potato I say potato. I don't think there is really any
objective measurment or criteria to use: it depends on many factors, almost
all of them specific to the situation and, therefore, alas,
idiosyncratic.Pros and cons for each situation.
One kind of unit I've made, though, for myself and others and have had
students make, too, is designed so that you place the bulbs facing up in a
box made so that your contact frame will flip over, face down, and sit on
top of the box, sealing it and eliminating any UV from leaking out (good,
beccause you may not "see" it, but UV is in the dakroom and its bad for
your eyes). The nice things about this type of unit is for those with small
dakrrooms or darkroom-in-a-kitchen set ups. The box is small, keeps
everything neat and tidy and is portable and, since it seals so well,
allows you to have the printer sitting out on a counter with no worries
about having your retinas quietly scorched over time. Also, you find a
sheet or even a half sheet of a veneered plywood, and you have a box that
is damned nice looking, too.
And, if you're in the market for a print frame, contact Doug Kennedy @
707-647-1447. He's a woodworker and photographer and designed and builds
what I think are the best frames out there. The springs are really strong
and mounted outboard of the center giving much better edge pressure. A
friend has one of his 20x24 frames and says it makes perfect edge to edge
contact. I've got an 11x14 and some 8x10's. He makes some of plywood,
others of pine and oak and cherry and so one has a host of finsihes and
prices to choose from, but they all have the same great squeeze.The oak and
cherry ones have dovetailed corners and are so damned nice to look at which
we know makes for better printing sessions.
So, bulb up or bulb down, happy printing.
Bill Laven