From: Stuart W Melvin (swmelvin@earthlink.net)
Date: 07/27/03-07:54:34 AM Z
Hey Sam,
I'm wondering if you might be able to elaborate on the viscosity of the gum
solution you use. Have you ever measured it with a baume meter? If not, what
ratios of water to gum (solution or powder) do you prefer?. Is your
viscosity preference consistent or do you find you vary it for any reason?
How does your viscosity preference relate to your application technique? So
many question marks........I must admire your technique hey.
Thanks,
Stuart
-----Original Message-----
From: stwang1@bellsouth.net [mailto:stwang1@bellsouth.net]
Sent: Thursday, July 24, 2003 10:48 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Re: Dry Dichromate and Gum, was Re: News from APIS
Hi Dave,
If I may jump in here, here is my way of using dry ammonium dichromate: I
add water to
gum to achieve the viscosity I need, add pigment till the color looks right,
THEN add the
required amount of dichromate powder. This way the viscosity and
concentration of
sensitizer are dealt with separately, and it will let me SEE how much
pigment I need to
put in. I understand this is a slightly different procedure as that used by
Stuart.
Another reason is that I prefer to use minimum amount of dichromate to do
the job. I
believe I use about 1/8 of what many others do. Yes, that means I need to
use it with
negatives of a lower density range (lower contrast), not a bad thing since
that means I
can print my negatives on the cheaper overhead transparency films (as
compared to
Pictorico).
Yet another benefit from the lower amount of dichromate is that less is
dumped down the
drain (and damage the environment).
On you question on applying gum by air spray, yes, it works just fine.
However, I would
strongly advise not to spray liquid gum WITH dichromate mixed in. Even with
just gum, I
would wear proper mask and eye protection.
I believe I have mentioned all of the above before, but perhaps no one
noticed.
Sam Wang
This archive was generated by hypermail 2.1.5 : 08/07/03-03:34:51 PM Z CST