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Re: [BKARTS] matching old paper



Peter, et. al.,

>Many years ago, we were advised that a particular make of English gravy
>>browning gave a good ageing colour to paper.

For the record (so far as I know) it was first laid down in print by
Bernard Middleton.

It is the sort of thing which may well have been known to the trade for
generations before Middleton published the fact.

>The gravy browning colouring we use is alkaline, as indicated above.
>Would >this property indicate its suitability for use in
>archival/conservation >practice? Perhaps the learned members of this List
>might wish to comment.
>
>Yours...
>
>Peter Krantz.


Well....  The pH scale is a logarithmic one; that means that a pH of
8 is ten times as alkaline (basic) as a pH of 7.

As we've all learned recently from Tom Conroy, acids embrittle cellulose
fibers; alkalies soften and enlarge them.

One of these days I've gotta buy another box of a nitrogen (alkaline)
garden fertilizer, just to take a picture.

My old box had lain in the garden shed for a couple of years before I
noticed it.  The thin card holding the nitrogenous fertilizer had absorbed
moisture and swollen.  A lot!

The printing on the box was readable, but the box fell apart when I tried
to take it away.

Too soft.

Conservation is a delicate balancing act.  We're never completely right;
we simply hope to not be completely wrong.

Jack

Thompson Conservation Lab.
7549 N. Fenwick
Portland, Oregon  97217
USA

503/735-3942  (ph/fax)

http://www.teleport.com/~tcl

"The lyfe so short; the craft so long to lerne."
Chaucer  _Parlement of Foules_ 1386

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