Light masking effects of polyester film

Elizabeth Hadlow <ehadlow [at] anmm__gov__au> writes

>We have noted several instances over the past couple of years where
>paper artefacts mounted with Mylar corners and strips have
>differential fading of the ink and/or discolouration of the paper.
>The area under the Mylar polyester film appears to be protected from
>light damage.

I have noticed this effect with a book that was on display for over
10 years, at a light level regrettably somewhat over 50 lux. The
area under the Melinex polyester film strip was hardly discoloured
at all while the exposed area was very discoloured. If not due to a
light blocking effect, I thought it might be because the Melinex
protected the paper from the oxidative effect of air generally
circulating in a very large walk-in case.

Alison Muir
Ulster Museum
Belfast


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                  Conservation DistList Instance 15:82
                  Distributed: Thursday, June 6, 2002
                       Message Id: cdl-15-82-003
                                  ***