Paper stored in vacuum

Jerry Shiner <keepsafe [at] interlog__com> writes

>Ercole Gialdi <rgi [at] mbox__ulisse__it> writes
>
>>Has anyone carried out studied on the ageing of printed paper when
>>conserved under vacuum?
>
>My first introduction to this method of paper storage was in 1992 or
>so. Multipak, BV of the Netherlands, had developed such a system for
>vacuum storage of documents (the ArchiPress system).

Like Jerry Shiner, I also came upon the Archipress System in 1992
when Conservation By Design limited became distributors for this
process. Since that time we have been researching its possibilities
and have gathered a great deal of practical empirical experience
regarding its uses and benefits including its highly successful use
as an alternative to freeze drying for the recovery of water logged
material and its reverse use for the humidification and the removal
of blockings from prints and photographs. The system certainly
reduces volume and protects against water, mould and insects. I
personally have not seen any evidence in the last 8 years of any
blocking or off-setting. In fact one of the remarkable things. I
have found during these experiments that it is possible to dry out
coated papers without them blocking.

With reference to the question of aging, some work has been carried
out on behalf of ArchiPress by Mr John B.G.A. Havermans of TNO
Industry in the Netherlands with relation to the proposed Armacon P
project instigated by Mr Peter Kissing. This project was looking at
the possibility of enclosing acid material in a partial vacuum with
a special gaseous atmosphere intended to raise the pH of the
material in the enclosure to create a kind of suspended animation
without permanently and physically altering the composition of the
paper.

As part of this testing TNO carried out artificial aging of acid
mechanical pulp paper and bleached softwood cellulose paper both in
and out of the Archipress high barrier pouches. These tests seem to
indicate that the mechanical strengths of both papers were
relatively unaffected by the vacuum packing although whiteness and
fold strength seem slightly better from the vacuum packed material.
The pH after aging of the pouched soft wood paper remained higher
than the "outpouched" material but the pH of the pouched acid
mechanical paper was lower than the "outpouched paper". TNO conclude
that:

   "Based on the approach, that the inpouch environment has to be
    equal to the outdoor environment during ageing studies, in our
    case 24 days at 70 deg. C and 55% RH, the conclusion can be
    drawn that encapsulation of paper using laminated uncoated
    polyester pouch and a slight vacuum, will neither influence the
    mechanical paper properties in a positive or negative way in
    time. However, paper deterioration will continue and paper
    acidification will even be enhanced by the paper encapsulation.
    It is suggested therefore that only for deacidified papers this
    accelerated acidification will not occur. Based on the
    artificial ageing experiments, care has to be taken for storing
    acid papers encapsulated."

        Extract From
        Ageing Behaviour Of Encapsulated Paper
        By John B G A Havermans
        Restaurator
        ISSN 0034-5806

I would suggest that the reason for this is that gases given off by
the acid mechanical paper cannot escape and therefore get absorbed
back into the paper. A similar effect has been observed in the
storage of degrading film (2) by Mr A Tulsi Ram of the Eastman Kodak
company who counteracted it by the use of molecular sieves. From my
own experiments I have found that acid mechanised newspapers stored
in a vacuum pack and then exposed to direct sunlight fade and
discolour at a substantially slower rate than the same paper outside
the vacuum pack. This is because U.V is an oxidizing process. To
counteract the effect offgassing from the acid mechanical papers we
recommend that paper should be interleaved or wrapped in
MicroChamber paper which contains activated carbon/molecular sieves
and an alkaline buffer for the purpose of absorbing any gases given
off by the enclosed papers and I am at present carrying out a real
time experiment to test the pH of a newspaper stored in an
ArchiPress pouch with and without Microchamber Paper.

Conservation By Design are also distributors for the Mitsubishi RP
systems of oxygen scavengers which also employ very effectively the
use of activated carbons and molecular sieves to absorb any harmful
gases trapped within the enclosed environment. If you wanted to have
a look at our Oxygen Free catalogue please visit
<URL:http://conservation-by-design.co.uk/>

Last year Conservation By Design co-sponsored the first
international conference "Noox" on the use Anoxic B storage and
treatments. The conference was hosted by Bob Childs of the National
Museums and Galleries of Wales in co-operation with Chris Collins of
the Geology Conservation Unit, University Of Cambridge, David Jacobs
of the British Library and Conservation By Design Limited. It seems
to have proved a great success and I hear that discussions are
already in progress for a follow up conference. I would be happy to
pass on further information regarding this conference to anyone who
is interested and it may also interest readers to know of the course
I am conducting in Montefiascone from the 14th till the 18th August
on the uses of vacuum and oxygen-free enclosures for drying water
damaged materials and the removal of backings by use of an oxygen
free enclosure. This is intended to be as experimental as well as an
instructional Course.

Details can be obtained from

    Cheryl Porter
    7 Venice Lodge
    55 Maida Vale
    London W9 1SD
    England
    +44 20 7266 0505
    Fax: +44 20 7266 0697
    chezza.p [at] virgin__net

(1) References:
    TNO Industrie
    Centrum TNO Papier en Karton
    Schoemakerstraat 97
    2628 V K Delft
    Netherlands

(2) And for further details on "The Storage Of Films Using Molecular
Sieves" article you can contact

    Mr A Tulsi Ram
    Eastman Kodak Company
    +1 716 477 5663


                                  ***
                  Conservation DistList Instance 14:1
                   Distributed: Monday, June 19, 2000
                        Message Id: cdl-14-1-003
                                  ***