jewelia (jewelia@erols.com)
Sun, 21 Feb 1999 23:33:49 -0800
in Prinmaking History & Process , saff and sacilotto, i found this:
"Many commercial machine-made papers are composed of wood cellulose fibers.
The quality of these papers has been improved vastly over the last quarter
century, and their stability and permanence often match those of
better-grade rag papers. This was not always so; papers made from wood pulp
during the years form 1900 to 1939 in particular have proven highly
vulnerable to deterioration. this is due to the alum-rosin sizing and
moisture from the air, which combine to produce the continuous formation of
acid in the paper fibers. Altough similar basic processes are still used
widely in the making of wood pulp, newer procedures for washing, isolating,
and sizing the cellulose fibers are now favored, yeilding less acidic, more
stable paper.
A new process for breaking down the wood pulp and isolating the cellulose
fibers from the resinous substances of the wood has been introduced
recently. The result, called alpha pulp, is made up of cellulose fibers
with a neutral ph balance and a longer fibrous structure than other pulp.
Alpha paper promises to be comparable to most rag papers in its longetivity.
Certainly, the newer alpha papers have a potential life many times that of
earlier pulp papers."
(and later)...."The alpha cellulose is that portion of the pulp or
cellulosic material in the wood that resists solution by sodium hydroxide at
ordinary temperatures. it is produced by briefly treating pulp with a 17.5%
solution of sodium hydroxide at 20 degrees C. Following the initial
merceritization and softening of the fibers, the solution is diluted to aout
9.5 percent sodium hydroxide, filtered, and washed with 10 percent acetic
acid and water to neutralize the alkali. Finally it is washed again to free
the fivers of acid. Alpha fibers are stronger and of greater length than
any produced by previous methods. Their neutral ph factor also ensures an
extremely durable paper--perhaps as durable as the best rag
papers....(repetive info deleted) many better-grade commercial papers will
be used increasingly for fine art editions.")
the book recommends the following offset papers as being excellent
long-lasting wood pulp papers for proofing. most have cut edges, no deckle,
and very smooth or slightly tectured surfaces. Also are ideal for
serigraphy:
Carrarra Cover
Index
Mohawk Superfine Cover
Mohawk Text
Weyerhauser Starwhite Cover
Tuscan Cover
Pericles Cover
anybody used any of these for alt-photo? and isn't one of those cotton rag
papers alum-rosin sized (is it platinotype??)
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