Digital BW, The Print

Bronzing is "dichroic" ...part of the pigment sits on the surface and
its nature is to reflect light differently from different angles. You
can see this in some photographic filters, or in the filters of
"dichroic" enlarging heads.

Urethane spraying is too much grief... the printer is obviously the
best tool for application. 

Some printers, maybe 1280s, may not register a second pass
precisely... but my 2200 and another that was mentioned earlier on a
"two pass" thread do register well within 1mm in a second pass with no
special registration efforts. 

WITH a pair of simple registration devices (3" plastic blocks) I've
read that tone-separation-precision (ie like a fine printing press) is
easy with 9600. Therefore a second pass applying Glop (or
whatever)should likely work, especially if the Glop rectangle exceeds
the size of the photo rectangle by a couple of percent. 

Yes, this is too hard for snapshooters (different printer ideally),
but I'm only interested in "custom printing" quality. 

> 
> I think we are all guessing as to what bronzing actually is -  what
is it that we are actually seeing?   

We're seeing the "dichroic" nature of the pigment...I think your
comment about "urine color" of Glop explains the killing of narrow
wavelengths.