Exhibition lighting for fluorescent ink

Alison Luxner <conserv.bac [at] yale__edu> writes

>We are planning an exhibition of contemporary prints, including two
>which are printed in fluorescent "glow in the dark" ink.  We plan to
>use a UV light source to make the ink glow.  The UV lights will be
>hooked to some sort of motion activated switch so we are not
>blasting the prints with uv light for the entire length of the
>exhibition.  The goal at the moment is to find a light source that
>is strong enough to make the ink glow, but not any stronger than it
>needs to be.

I visited an installation this year in which the patrons were given
small hand-held UV lights at the entrance, which we were expected to
use to light our way through the darkened gallery.  (However the
fluorescent materials were intended to be ephemeral, unlike yours).
I don't know that this would work in your situation--the prints
probably need more overall illumination than would be possible from
a small source.  However, I expect the smaller the source the less
exposure.  (Another problem with the hand-held lights was the
batteries needed to be replenished frequently).

I don't have any information about UV levels from typical UV lights.
However, it occurs to me that if you can get this information, it
might be worthwhile to compare the total exposure you expect from
this scenario with what you might expect if you did allow a little
UV into the "normal" viewing conditions.  For instance, standard
halogen bulbs put out some UV (more than tungsten do) and put out
more the higher the dimmer is set.  If you have access to a UV
meter, you could determine the lowest level of lighting which will
produce the phosphorescent (glow in the dark) effect.  If you
illuminated the prints at this level, the viewer could turn *off*
the lights in order to see the phosphorescence, instead of turning
*on* UV lights to see fluorescence.  This only makes sense, of
course, if the total UV exposure over the course of the exhibition
would be similar or lower, and if the logistics of installation were
significantly easier (and, depending on the curator, if it fitted
the desired viewers' experience of the exhibit).

Another thought--have you considered glazing materials?  Because
even non-UV filtering Plexi does cut out some UV, as does glass to a
lesser extent.  It would be worthwhile to check this out before
installation, otherwise you might inadvertently kill the effect. (In
practice, I have found that standard (non-UV) Plexi will cut the UV
from halogen bulbs down to levels comparable to tungsten, even at
high levels of illumination--and I'd be interested if other people
can corroborate this).

I would expect the florescent materials in the inks to "fade" after
exposure (how much exposure, I don't know).  I believe Andrew Robb
has done research on fluorescent brighteners in photographic papers
"fading" over time, which might be comparable to your problem.

Laura Downey

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                  Conservation DistList Instance 12:54
                 Distributed: Friday, December 18, 1998
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