Archival quality stuff...

Jim Croft jrc at ANBG.GOV.AU
Wed Jan 20 08:16:56 CST 1993


> From: Aaron Liston <listona at BCC.ORST.EDU>
> Subject:      archival quality question
> To: Multiple recipients of list TAXACOM <TAXACOM at HARVARDA.HARVARD.EDU>
> Date:         Tue, 19 Jan 1993 10:16:17 PST
>
> Taxacom Readers:
>
> Has anybody compared LaserJet vs. InkJet printers for archival
> applications [e.g. herbarium labels]?
>
> Are the "glue stick" adhesives of archival quality?
>
> Any information and/or references concerning these products would
> be appreciated.
>

The following are some notes of our experience here at Canberra.
For detailed references, your local archivist should be able to produce
a mountain literature.  A posting to one of the librarian's networks
will probably produce a heap of responses.

Printing
--------
At the Herbarium of the Australian National Botanic Gardens (CBG) we
have been using herbarium specimen labels printed on archival quality
paper for many years, a decision based on the fact that since the
pigment contained iron and carbon, there would still be marks on the
paper in centuries to come, ie. the pigment was unlikely to fade.
Inkjet ink also contained carbon and was also considered acceptable, but
at the time the decision was made, laser printing was of better visual
quality and Postscript inkjet printers were not available.

Investigations into the suitability of this technology in the herbarium
and outside in the living collections on 'plastic papers' revealed that
laserprinter and photocopy pigment was hydroscopic and when moist would
slowly flake off, in effect, rust.  With the relatively stable and low
humidity in temperate herbaria this may not be a problem, but in non
air-conditioned tropical herbaria it might be (but vanishing ink is the
least of your specimen maintenance problems in such environments).  The
problem was found to be significant for outside labels and some form of
water impervious coating was advised or a different printing technology
such as thermal transfer that did not contain iron and melted the
pigment into/onto the medium.

[ On a related issue we are looking for a supply of stock of UV-stable
  waterproof paper substitute for printing horticultural labels that
  will hold printing and last in full sun for at least 5 years.  Does
  anyone have any ideas?  Is anyone doing it already? ]

Specimen accession barcodes at CBG are printed by laser printer and are
included as part of the label.  Abbrasion may be a consideration where
the physical contact of a barcode wand is involved.  The laser printed
barcode could withstand 200 passes (by which time I tired of the test)
of the wand without dectectable deterioraton of the barcode.  As it is
unlikely that a barcode will be scanned more than a dozen times a
century, I do not think abbrasion is an issue here; the use of scanners
rather than wands could perhaps be recommended as a standard for
herbarium/museum use.

We also use laser printing to print label information, barcodes, etc,
directly onto heavy paper packets for mosses, liverworts, etc.  This is
quite efficient but the choice of paper stock is critical.  Some
archival papers had a short fibre length and would not fold into packets
without cracking, others had a particular finish that would not allow
the laser ink to bond strongly or completely.  That latter caused the
pigment to smear and rub off when two printed surfaces were rubbed
strongly together, although not to the extent that the words could not
be read.  As the packets were filed vertically without covering folders
and rubbed against each other as they were taken in and out of the
drawers, this was considred inmportant.

Gluesticks
----------
We had not condsidered the use of 'glue sticks' in a specimen curatorial
context, not because of concerns about the chemical composition of the
glue itself and how this may effect the substrate, but because of the
strength and permanancy of the glue.  The types available here are
designed for office use where it is possible to peal off the glued item.
This is not someting we want for herbarium labels and deteminavit slips.
However, I have seen such glues advertised in archival and library
catalogues as being stable and non-destructive.  We would be very
interested in what people have to say about this glue.

Similar Curatorial stuff
------------------------

CBG has adopted a commercially available self-adhesive acryllic tape for
the mounting of herarium specimens.  The archival qualities of this
material are very good and with definite length dispensors it is
certainly and efficient method to mount herbarium specimens.  If people
are interested, we can send details of the product and the technique
employed at CBG.

jim

ps. Whatever happened to the question of herbarium/museum insect control
    posted to taxacom some time ago?  Perhaps we should set up an area
    of the taxacom ftp and gopher servers for this kind of specimen
    management and curation information?
____________________________________________________________________________
Jim Croft                [Herbarium CBG]           internet: jrc at anbg.gov.au
Australian National Botanic Gardens                   voice:  +61-6-2509 490
GPO Box 1777, Canberra, ACT 2601, AUSTRALIA             fax:  +61-6-2509 599
______a division of the Australian National Parks and Wildlife Service______




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