Older "archival" products

Re Dan Clements's observations on early "acid-free" boxes, this is
probably the most misunderstood concept in preservation, even among
people who've had some (non-conservation) training.  For once and for
all, "acid-free," like "archival-quality," is a meaningless term for
preservation purposes.  These terms only mean that the vendor has
learned we recognize that term and will buy storage materials on the
strength of it.  Hollinger document storage cartons marked simply
acid-free, like the similar Paige boxes, are made out of woodpulp
corrugated board.  The material has not been chemically processed to
remove lignin or other potential pollutants, nor has it been alkalized
by the addition of a buffer.  Consequently it will acidify from its
just-manufactured neutral state quite rapidly given warm and/or humid
storage conditions.  Thus the finding of pH 5.0 in aged Hollinger (or
Paige, or other acid-free boxes). Newer boxes of the same material have
not had enough time to develop significant acids, but they will do so
over time.  If you ask Hollinger if these boxes are "archival" they will
tell you no -- they're intended for temporary storage of material on a
retention schedule.

If you want true "archival-quality" boxes you must look for material
described as "lig-free" (another misnomer) or low lignin; "buffered,"
(often "pH approximately 8.5"); and "alkaline reserve" (often 2% or 3%).
You must also match the type and size of the box or other enclosure to
the size and format of the material to be stored in it.

To go on, a few things should not be stored in buffered enclosures.  The
most common are hand-colored material (such as water colors or maps),
blueprints, and cyanotypes.  The coloring agents may react with the
buffering chemicals to discolor.  For these categories use "pH neutral"
(approximately 7.0) storage materials or stable plastics.  The word is
still out on albumen prints, but IPI is working on a scientific answer.
In the meantime, the conservative choice for albumen prints is also
neutral storage, although Jim Reilly has said if you have dry, stable
storage conditions, buffered enclosures should pose no problems.

Karen Motylewski

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                  Conservation DistList Instance 6:49
                  Distributed: Friday, March 12, 1993
                        Message Id: cdl-6-49-007
                                  ***