this is a direct quote from the light impressions (good resource for
archival supplies) website www.lightimpressionsdirect.com:

"What is the difference between buffered and non-buffered storage papers and
mat board?

Buffered paper and board have calcium carbonate added to raise the pH level
to 8.0-8.5. The buffering agent neutralizes acids that could potentially
harm your work. They work best for the storage and display of Black & White
photos and artwork on paper. Non-buffered paper and board have a pH level
between 7.0-7.5. There is no buffering agent, since it may adversely affect
some materials, causing color shifts or changes. Non-buffered materials are
intended for use with albumen, cyanotype, dye transfer, and color prints
(chromogenic), as well as protein textiles."

hope this helps...
-- 
Jennifer Uhrhane
[log in to unmask]
http://www.detailphoto.com

> From: Kimberly Radtke &/or Keith Routley <[log in to unmask]>
> Reply-To: Museum discussion list <[log in to unmask]>
> Date: Sun, 30 Nov 2003 20:17:28 -0800
> To: [log in to unmask]
> Subject: buffered or unbuffered mats?
> 
> I am matting some botanical prints from the 18th/19th century by Curtis and
> Edwards and understand that they may have been hand tinted. Anyone know for
> sure if I should use unbuffered or buffered backing and mats or have a
> source of definitive info? I've checked a number of sources, such as NEDCC,
> CCI notes, but can't find anything specific. Thanks, Keith
> 
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