>>    [UV LEDs]
>    Question is wattage.

Well, my observation is something like "more watts per unit emissive
area than the tradtional BLB fluorescent bulb, and more easilly
focusable to a point as well.  Of course, BLB exposures for most resists
are on the order of 10 minutes, right?  Getting intensities high enough
for "human visible" plotter speeds is probably quite a challenge with
any UV technology.  Even those high-intensity UV curing guns your
dentist has need multiple 10s of seconds of exposure...

I wonder if there's some sort of dual-chemical system that could be
used.  Coat board with (water soluble) Part A, injet or plot with (water
soluble) Part B.  Where they touch each other, you get water-insoluble
and etchant-resistant substance C.  Wash off the extra "part A" and
you're all set.  Alcohol soluble chemicals might work too (Hmm.  And
that might include epoxies...)

OTOH, Metal capillary (hypodermic?) tubes filled with melted wax have some
attractions.  No clogging just because some solvent evaporates...

BillW

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