The
History of Archival Boards in the U.S.A.
and
MicroChamber Technology
The first attempt at producing an
archival board for preservation housings in North America was made in the
1960s. This first boxboard, gray with a red pulpy center and a pH of 6.5 was
considered to be at the leading edge of archival storage technology.
Information that acids were the root cause of paper deterioration was beginning
to be widely disseminated among those concerned with preserving documents,
books and works of art on paper. By todays standards, this mildly acidic board
would be unacceptable for use as a preservation housing; however, at the time,
its production was quite an achievement. The board mills of this era all
utilized acid paper making systems, and even this mildly elevated pH level
caused severe problems for the mill which produced it.
This was the period when Frazer Poole
was beginning to lead the US Library of Congress preservation program into new
areas. The Library quickly established new standards which required a pH of 8.5
for preservation housing boards. The paper adapted for this purpose was an
unbleached (therefore brown) kraft. It retained its full complement of lignin,
and no alkaline buffer was added. Unfortunately it did not retain its alkaline
pH for long. The solution to this problem was thought to be the addition of
calcium carbonate as an alkaline buffer. However, as time passed, it became
apparent that the addition of alkaline reserve did not prevent the pH from
dropping into the acidic range in boards containing lignin.
Further progress was made in 1979 when
Conservation Resources introduced the first gray boards made with quite low
levels of lignin and alkaline buffering distributed evenly throughout the
entire board. In 1980 another advance was made Conservation Resources
introduced the first lignin-free and sulfur-free alkaline buffered board,
produced initially for the Library of Congress.
The goal, until very recently, was to
produce stable archival papers and boards which would not break down and
contribute to the deterioration of the collection housed within them. With the
removal of lignin and other substances which promoted further deterioration,
and with the inclusion of alkaline reserve throughout the board, we thought we
had achieved the ultimate in archival storage housings: a truly non-reactive
housing that met our passive preservation goals. However, as observational and
experimental knowledge increased, it became apparent we needed to find
additional methods of dealing with the shortcomings of contemporary archival
alkaline buffered preservation materials.