Ashley,

My understanding is that the "oily" rainbow effect is typically the result of plasticizers in materials that contain vinyl(probably PVC) migrating to the surface. It will make them tend to stick together as well. In any case the appearance of that material over time is unquestionably bad for the objects stored within.

You should probably do a little basic testing to determine what it is, and if you really need to replace them. Basic stretch/burn/melt tests should tell you what you have.

Mark Janzen
Registrar/Collections Manager
Ulrich Museum of Art
Martin H. Bush Outdoor Sculpture Collection
316-978-5850

From: Museum discussion list [mailto:[log in to unmask]] On Behalf Of Ashley Tate
Sent: Wednesday, January 16, 2008 1:04 PM
To: [log in to unmask]
Subject: Oily Photo Sleeve

I have noticed a strange effect on some of the photograph sleeves currently housing photos in our archives. The sleeves are clear, maybe polyester. And some of them have what looks to be moisture inside the sleeve. The "moisture" has a swirly rainbow look, like you might see if you spilt oil on pavement on a sunny day. At first I thought it was moisture trapped in the sleeve, but now I'm wondering if the effect is just part of the material. Do any of you know what this could be?

Thanks!
Ashley
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