I would be a little careful about blanket statements. Some early maps, 
notably those on laid paper, arguably do not need deacidification. There 
could be considerations regarding early color and the need for 
additional restoration related to the deacidification process itself. 
Some institutions are not prepared for mass deacidification 
(http://loc.gov/preservation/about/deacid/index.html). In terms of the 
observational window, a decade might not be long enough for evaluation 
of some materials. This can get tricky 
(https://www.nedcc.org/free-resources/preservation-leaflets/7.-conservation-procedures/7.5-conservation-treatment-for-works-of-art-and-unbound-artifacts-on-paper), 
and institutional budgets might also alter considerations.

I would be curious as to how some of the folks at the G&M division of LC 
approach these decisions.

         Joel Kovarsky

On 1/6/15 9:44 AM, Angela R Cope wrote:
>
> As has been pointed out, encapsulating a map without de-acidifying it 
> first may be bad for the paper. But, I wonder what would be worse - a 
> brittle or fragile map being damaged while handling or the quickened 
> degradation of the paper inside the plastic sheets.
>
>
> I guess I have another 10+ years ahead of me. I'll do an experiment. 
> Watch Maps-L for the results in 2025.
>
>
> :-)
>
>
> Seriously though, I'll start this week and post pictures to the AGSL 
> Flickr pages.
>
>
> Angie
>
> AGS Library
>