Herbarium materials

Eeva-Maria Tikka <emtikka [at] mappi__helsinki__fi> writes

>Does anyone have experience how to create an air filtering (HEPA)
>system for cleaning of non-standard size herbarium sheets containing
>hazardous particles?
>
>I suppose e.g. PEL Cleaning Machine with a Herbarium Top is designed
>for the standard size vascular sheets, but it's not suitable for
>tiny lichen specimens glued on very small labels.
>...

The PEL Cleaning Machine will work on non-standard herbarium sheets
using the standard top that comes with the machine. What you need to
do is mask off the areas of the top that you are not using with
polythene about one inch away from the sheet you are working on.
Obviously you don't want a hurricane blowing through the holes, so
you need to leave a fair portion of the top open to regulate the air
flow (but well away from the work).

I usually mask off the complete side of the top where I am working,
leaving an inch of free holes surrounding the sheet for downflow,
and on the opposite side of the top, I have an exposed set of holes
(about two inches wide running along the whole length of the
platen). I cover these holes with a separate polythene sheet which
I slowly draw back until I have the speed of downflow that I require
running through the edge holes by the sheet. It is not as good as
the platen we had made for RBG Kew's standard herbarium sheets, but
it  works for our few non- standard sizes of lichens and mycology
specimens.

Of course, if you have a lot of sheets, you could always commission
a sheet-specific top to be made for you.

Jonathan S Farley
Senior Conservator
Royal Botanic Gardens, Kew
Richmond, Surrey TW9 3AE
England
+44 208 332 5419
Fax: +44 208 332 5430


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                  Conservation DistList Instance 15:24
                Distributed: Tuesday, September 18, 2001
                       Message Id: cdl-15-24-005
                                  ***