phillip murphy (dag39@goplay.com)
Fri, 19 Feb 1999 16:48:36 -0800
Odd, I sent this message to the list earlier today
yet received no confirmation. Forgive me if this
has already appeared.
"Keepers of Light" has a brief overview of the process as
well as a few illustrations. You're correct in saying
that the process required a great deal of hydraulic pressure.
4 to 5 tons to the square in. was about right;
making a 4x5 print required a press capable of 100 tons.
An 8x10 ?
The notion was derived from "Nature Printing". Originally,
Woodbury did not use the hydraulic press for making
his molds. Electrotyping was used and also the molds
were cast using plaster. These methods have their
drawbacks especially when it comes to planarity.
The hydraulic press technique made the process commercially
viable.
Woodbury did not stop there. He later invented a modified
technique in which tinfoil was used to face a reversed
matrix thus creating a printing plate without the use
of a hydraulic press.
Another means of making the printing plate was patented
by another party in which a rolling mill was used to
provide the necessary pressure. This could also be
made into gravure-like plate by laying a textured layer
on the matrix as it went through the rolls.
The only person currently working the process to my
knowledge is Vincent Hoban who used to be a
member of this list.
all the best,
Phillip Murphy
dag39@goplay.com
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