The message below is reposted without the knowledge of the author.
Some of you list members may aready be aware that the Dupont product known
as Mylar Type D ( recommended by conservators for many years as a suitable
material for encapsulation of historical documents and photos)  is
eventually no longer going to be available. Dupont has ceased production of
this particular polyester film product and once current supplies are sold
there will be no more I understand.  However as the posting below from the
Library of Congress Conservation Division states various people in the
conservation field are already seeking out suitable alternatives.  I'll keep
you posted as I learn of more sources and materials.

Iona McCraith
AAO Preservation Consultant
Bethany, Ontario
Tel: (705) 277-1309
Fax: (705) 277-2091
e-mail: [log in to unmask]
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Date: 20 Feb 2002
From: Amparo R. De Torres <[log in to unmask]>
Subject: Polyester film

Library of Congress update on acceptance of polyester film products
for use in paper encapsulation

Polyethylene terephthalate (PET) films such as DuPont's Mylar D and
ICI's Mellinex 516, which we have recommended in the past for use in
encapsulation and other book and paper conservation practices, are
no longer being manufactured.  Therefore, we are actively engaged in
qualifying for our use suitable alternative products from other
manufacturers.  Thus far, we have determined that Hostaphan 43SM
film made by Mitsubishi Polyester Film, LLC, of Greer, SC, is an
acceptable substitute for use in our conservation laboratories.

Other interested manufacturers are invited to send samples for
laboratory testing and approval to the attention of Chandru J.
Shahani, Chief, Preservation Research and Testing Division.  As it
develops, we will continue to post information about this subject at
<URL:http://www.loc.gov/preserv/>.

We are pleased to share information about product testing with the
preservation community, with the understanding that information
concerning favorable test results in no way implies product
endorsement.  Vendors are strictly prohibited by law from implying
or claiming that the Library of Congress endorses any specific
product, service, or material.

Amparo R. de Torres
Special Projects Officer
Conservation Division, LMG 38
Library of Congress
101 Independence Ave, SE
Washington, D. C., 20540-4530, USA
202-707-1120
Fax: 202-707-1525