Laser pointers

J. Claire Dean <clairedean [at] aol__com> writes

>Does anyone have references or thoughts with regard to the possible
>longterm impacts of regularly using laser pointers (the small hand
>held type used to indicate points of interest on a screen when
>giving a slide presentation) to highlight areas of interest on works
>of art?

I tested a few Australian Standards Class II laser pointers.  The
test was simply to mount the unit in a vice 25 mm. (about 1 inch)
away from an already discoloured piece of paper which was about as
delicate an item as we could come up with.  In retrospect, I should
have used blue wool standards.  The pointer was turned on until the
batteries died- about 17 hours was the maximum we got out of any of
them.  The distance should not be a critical factor as the light
energy is parallel, but I wanted to maximise the exposure to see if
there was any possible problem.

I could not detect any deterioration or discolouration in repeated
tests. We cleared the Class II pointers for used by voluntary guides
and education department.

In practice it is very hard to hold pen size pointers still enough
to create continuous exposure of any one area for very long--the
actual beam of light is very tiny and in normal use, the beam
wanders around in random small circles.

The Australian Class II standard is what all the commonly used and
relatively inexpensive laser pointers are labelled here and I
presume there would be an equivalent standard elsewhere.  I have
been told that one of the main issues with the standard was to set
the power low enough to minimise the possibility of these devices to
unintentionally or intentionally cause blindness.

I am particularly comfortable with their use as the alternatives may
be much worse.  I have walked through our gallery on various
occasions to see a visiting scholar or teacher looking at their
audience while over their shoulders, pointing or even gesticulating
wildly with a Bic pen oblivious to the fact they are a few hair's
breadth from doing horrible damage. Using laser pointers, they stand
further away and seem a lot less of a threat to the works on
display. I understand we have had many of these pens disappear,
however.

Thomas Dixon, Chief Conservator
Conservation Department
National Gallery of Victoria
180 St Kilda Rd
Melbourne  Vic  3004
Australia
+61 3 9208.0348
Fax: +61 3 9208 0249

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                  Conservation DistList Instance 10:58
                Distributed: Tuesday, December 17, 1996
                       Message Id: cdl-10-58-002
                                  ***