Thanks to those who responded to my question about the different types
of UMI microfiche.  I did not know there was any problem mixing the two
types in storage.  If anyone from UMI is listening, I would like to hear
more on that topic.

The following is a message I received from Paul Crandall of UMI and since
there still seems to be some interest on the topic I though I should
forward it to serialst.

------- Forwarded Message Follows -------
Date:          Mon, 3 Feb 97 14:18 EST
From:          "Paul Crandall" <PCRANDALL@umi.com>
To:
kstetson@fairl.fairfield.edu,imoss@PEACE.EDU,dyanney@COLEMAN.PVAM.EDU
Subject:       UMI microfiche
Cc:            ABOLHOUSE@umi.com,PCRANDALL@umi.com

Hello -- I've run across your question about silver & vesicular microfiche &
wanted to reply...
Mr. Stetson is correct that silver film has greater life expectancy than
vesicular -- 500 years compared to 100 years, assuming proper storage
conditions. Bob Mottice, UMI's technical expert on microforms, says silver
offers higher resolution and better reproduction for high-detail work, like
superscripts, subscripts, etc. Old-source materials and even newer materials
that were poorly printed as originals (newspapers, especially, come to mind)
will come across a little better in silver. He says silver is also a little
more durable from a mechanical standpoint -- the same amount of patron
use/abuse may cause more image loss in vesicular film than in silver. On the
other hand, vesicular accepts more relaxed storage requirements with regard to
humidity. High-humidity storage invites molds and fungi into the gelatin-based
emulsion of silver film -- less of a problem with vesicular.

Please feel free to post this to your list if you think it's appropriate.

Thank you for your interest.

--Paul Crandall
_____________________________________________________________
UMI--The Answer Company (TM)                    Paul Crandall
300 N. Zeeb Rd.                    Serials Product Specialist
Ann Arbor, MI 48103                         800/521-0600x3244
USA                                         pcrandall@umi.com

Donna Sue Yanney
Assistant Periodicals Librarian
Prairie View A&M University
donna-yanney@tamu.edu
Phone: (409) 857-2756 FAX: (409) 857-2755