> Judy says:
>
> >My "slow" gum that's nearly used up is 20 years old. But it's a
> >commercial lithographer's gum, may have been cooked by them. In any
> >event, I've never noticed a change, though it may have been glacial.
>
>
> Haven't we heard at sometime on the list that "lithographers gum" isn't
> really gum arabic but is really a synthetic polymer? Possibly it is
> polyvinyl alcohol or a similar stuff? This cropped up somewhere in my
> research on gum.
>
I know, Dick, that you don't believe everything you hear, because I
myself, personally, have told you things you didn't believe.
So, yes, we've heard that (and I recall from whom, though I spare him this
expose, as he is generally a fount of utterly marvelous information and
knowhow), among other random error we have, do and will hear on this list
and elsewhere.
For one thing, PVA is generally much more expensive, so why sell it for
less than it brings? For another, what crook (and s/he would have to be a
crook, since the label says "pure gum arabic") would add colorants to make
their "gum" dark brown when natural PVA is relatively if not completely
pale? For yet another, many customers would know the difference and raise
holy hell...
Etc. Etc. Etc.
Judy