Re: A PVA for printing "gum" from Mike Ware

On Wed, 29 Mar 2006, Katharine Thayer quotes Mike Ware as saying that:

> .... they settled on was a "polyvinyl alcohol-acetate; i.e. only
> partially hydrolysed co-polymer, which is much more easily dissolved in water
> than the pure alcohol. We found an 88% hydrolysed PVA, with an RMM around 25
> kD in 20% w/v solution, to offer the best all-around results-- comparable to
> a 14 Baume Gum."

I have read, or tried to read the 5,380 posts on making gloy, or gloy
substitute, or a gloy-like substance that accrued in the 20 minutes I was
offlist, but now I surmise from this citation that 14 baume gum is (still)
the criterion. That's a substance I buy by the gallon -- now somewhat up
in price, it seems, but last time my favorite was just $16. (About 8
British pounds, I gather.) Can someone explain why that's not good enough?

(Any commercial printing supply source should have it -- even in Turkey,
perhaps. And it keeps forever -- the preservative is already in it. They
probably sell to anyone, too, even a reckless photographer.)

J.
Received on Wed Mar 29 17:24:46 2006