jewelia (jewelia@erols.com)
Thu, 18 Feb 1999 11:44:14 -0800
sulfite papers are made from wood pulp -- beyond that i''l give it a shot--
i'll suspect a few corrections & additions here -- perhaps a lot--its been a
few years-- wood pulp is celluose - or better yet lignocellulose -- the
lignin is not so good stuff -- makes sort of a tar i think--it is used to
make certain adhesives--and lignin may be removed for better papers i
think --can't recall-- i know it is for stills--so i am guessing it is not a
good paper component at all as far as conservation goes. the bulk of it
75-80% is the cellulose--like cotton linters as a matter of fact--trees are
just sugar only very tightly chemically bound together--beyond what we can
digest in fact--or we could just eat trees--to break up these bonds -- to
make pulp for paper exists several options--the cheapest is acid
treatment--just singe the heck out of it but not so much you completely
destroy the cells--only mostly. make cardboard boxes and other nifty
things-- sulfites i believe are another option -- i think they can help
break these bonds and sulfites are a preservative as most of you know --
oxygen scavengers so may be used for this and tend to do some other
things--bleach a bit or what have you. really white papers used to be
bleached out with well basically clorox and this was a major source of river
pollution-- dioxons-- i believe this has been regulated away. the last
method of pulp prep is by the use of enzymes--this is rather recent
technology and i doubt any paper we would use is made this way. i believe
the industry calls wood pulp papers used for better things like art sulfite
papers because better wood pulp papers are processed with more sulfite and
less acid that wood pulp used for "general purposes" i imagine this was the
beginning of our acid-free hysteria--btw: not only are buffered materials
bad for us and some other areas of photo--i recall the curator of prints and
drawings say it turned out to be a big mistake and they have or are
rematting every work on paper they own. but traditions die hard--good or
bad.
if your paper is really really smooth it is probably sulfite because it is
more a pulp than cotton linters or linen fibers etc which can be broken up
more easily by mechanical rather than chemical means (they use beaters and
stamping mills to rip them apart)--wood pulp does have a fiber though and
the better sulfite papers are made with the better, longer fibers, as paper
is recycled the fibers are mascerated more and more--generally what is
recycled white --the best of it can only be used as a component of a
"better" paper and the rest for newsprint--about 40 percent i think goes
down the drain. i would guess that most silver gelatin papers have a lot of
sulfite in the actual paper part if not all of it. artists have been
drawing on sulfite papers for a long time.
no its not cotton. but--i mean c'mon cotton linters aren't everything.
my source: had a nightmare i wrote a couple of papers like "Technical and
Economic Feasibility Analysis of a Hypothetical Prototype 1-Million GPY
Ethanol Fuel from Lignocellulose Commercial Production Plant using
State-of-the-Art Enzymatic Hydrolysis Technologies" once upon a time. its a
long story my friends.-- just thought cars burning alcohol fuels would be a
good idea--unfortuantely i think i am the weakest on the sulfite area
because this chemical wasn't much involved for this particular
application--jewelia
This archive was generated by hypermail 2.0b3 on Sat Nov 06 1999 - 10:06:51