Yes, Gloy is "said" to be faster than gum arabic, but in the, admittedly
unsuccessful, tests I did with Gloy I found that it wasn't. At least it
wasn't faster than the particular gum I was using at the time, nor even
quite as fast.... Perhaps under a set of other variables it might be
faster than gum arabic used with the same variables, but just hearing
folks say it's "faster" is hardly conclusive. In fact I believe the
one who started that story may have been Terry, but it turned out that he
changed from potassium dichromate to ammonium dichromate at the same time
he switched to gloy. Ammonium dichromate (saturated) is definitely faster
than potassium dichromate (saturated).
As I recall Larry Shapiro also said he found gloy faster, but, again,
faster than what?
In any event, I've never seen it matter, since an exposure of 3 minutes is
hardly a major advance on an exposure of 5 minutes. However in this case,
for masking purposes, you're quite right, it does matter.
> you don't like Gloy but I am using it as an example of speed. In the
past, Le Pages mucilage was used, though I don't know if that is available
anymore. >
I have not tried Le Pages glue, but I made a series of tests with
rabbitskin glue. Again, there are assuredly ways and ways, but I could
never get it to make a continuous tone without brushing.
> Your idea of fast and slow gums is very very interesting and something I
> want to investigate from the commercial side when I get back to
> developing gum kits.>
Dick, it's not my *idea* -- it's my *finding.* If I solve the mystery
I'll license it to you. ;- )
Judy