RE: shrinking Masa
Since I currently print small (around 16 x 24cm, 6 5/16 x 9 7/16") and
my subject matter is often very detailed and textured, even the
slightest registration problem is disappointing to me. If I were
printing large (>= 30 x 40cm / 11 13/16 x 15 12/16" that is) that
wouldn't bother me at all, but it does now... Maybe I should leave back
my urge for detail and sharpness when doing gums - but I'm not ready to
give up yet.
I apply the adhesive only to Yupo by means of two perpendicular coats. I
tape Yupo to a larger scrap sheet tacked to the wall, spray, quickly
untape it and put it down onto Masa laying on its front (back surface
looking up - I lower Yupo onto Masa a la Albumen, by bending it) and
press it with my palm (starting from the middle, towards the edges and
corners). The whole operation (including taping) does not take more than
30 - 45 seconds. I use the paper the next day. If Yupo is too costly you
can do it on alternative substrate such as Mylar. (Maybe that would be
better, since UV won't reflect back from the base; I had to cut exposure
by 1/3 stop, for paper affixed to Yupo...)
From: Rajul [mailto:firstname.lastname@example.org]
Sent: Thursday, September 06, 2007 7:34 PM
Subject: Re: shrinking Masa
I have shrunk Masa as described on Sept 4 for 1.5, 3 and 4.5 hours.
These were coated with the traditional 2A + 1B emulsion, exposed,
developed, dried and checked vs. the neg for shrinkage.
Whereas the 1.5 h-soaked paper showed a uniform shrinkage of ~1mm all
around, the 3 and 4.5 h soaked sheets shrank slightly more, providing
for improved registration. I consider this acceptable unless further
experience is contraindicative.
I gelatin sized all of these, dried, then flattened them and found that
the shrinkage described above still held. I will do gum passes on these
aligning the neg as closely as I can to the centre of the image (which
is quite intricate).
I have also heard from 3M and they suggest that 3M Photo Mount (no
catalog number specified) is the most appropriate product to get Masa
to adhere to Yupo. They recommend evaluating it by applying to one
surface (normal method) and, if necessary, on two surfaces. A two
surface bond will be like a contact adhesive - no repositionability.
They do not have data to state how well it will work in different
moisture and/or chemical environments.
I think I will stay with the shrinking protocol and forget about
mounting Masa on Yupo. This seems to work in my hands.
I hope this helps. Rajul