Re: Substrate and gum

CHRISTOPHER TSOURAS (tsouras@nevada.edu)
Wed, 14 Aug 1996 10:13:20 -0700 (PDT)

My two cents in regards to gum substrates/registration: I=D5ve been=20
happily gum printing away for the last few years and have been most=20
satisfied with the incredibly tight registration, print contrast, and=20
color saturation (despite W. Crawford/Keepers comments) that I have been=20
able to achieve with a rather simple (covered by others in the archive) 2=
=20
pin registration technique. =20

In my humble experience what appears to be of paramount import is my=20
initial shrinking of the paper. Regardless of the particular paper I=D5m=
=20
using (which more often is BFK Rives, Magnani Italia, or Strathmore=20
Drawing) I place the paper in a deep tray of hot water (hot as possible)=20
for a minimum of thirty minutes, turning the sheets every few minutes. =20
The paper is then hung to dry. After which I bake the hell out it in an=20
old platen print dryer for a minute or two. I suppose you could do the=20
same in any dry mount press. I=D5m placing the paper between blotter paper=
=20
so the platen will not affect the papers surface. =20

The next step, of course, is sizing & hard sizing the paper. After which=
=20
I again place the paper in my platen dryer; but this time only briefly to=
=20
flatten the paper. During each step in the pre-processing steps as well=20
as throughout the printing cycle I make every effort to hang the print=20
whilst it dries by alternating corners. After the final sizing I then=20
punch my registration holes. The paper at this point is remarkably rigid=
=20
and I feel I really get clean punched and durable registration holes. =20
Despite the use of heat drying during pre-processing steps I am able to=20
maintain impervious sizing typically for four to six printings worth=20
(after which I=D5ll hit the print with brush applied sizing between print=
=20
runs).

The rationale behind this is rather obvious. The principle papers we are=
=20
using are typically 100% cotton, like my king size cotton bed sheets=20
which if washed in extremely hot water and dried with heat will end up=20
queen size (shrunk in all directions). The heavy pre-shrinking=20
(certainly not a new idea) I utilize allows me to consistently print=20
large images with meticulously accurate registration using simple 2 pin=20
registration.

Christopher Tsouras
tsouras@nevada.edu