>Now that I have lost my urge to ball mill pigments, temporarily at least,
>I'm thinking about gum. My feeling is that what makes one gum better is the
>impurities or more precisely the lack of impurities. I made liquid from
>powder years ago and as I remember, it was pretty dirty looking. We make
>liquid developers from technical grade chemicals, they too come out when
>dissolved to be real dirty but they clean up with an overnight cycling
>through a charcoal filter. I was wondering if the same would work for the
>gum. I could make up a 50 gallon tank at say 20 Baume and remove all
>reactants and clean it up with charcoal so it's nice and white. The user
>could then dilute with water to the desired Baume using a chart or nomagraph.
>
> What is your feeling, if any, about what makes on gum better than another?
>I know you said you had few conclusions but you might have some intuitions.
>
>Thinking out loud.
>
Yes I believe impurities do affect the gum. I also wonder about ph since it
is different for different gums. However impurities may help. Many folks report
that their best results are with lithographers gum, which is the darkest
and cheapest. The premium gums sold by winsor & Newton and Daniel Smith
are selected or processed? for lightest color and least impurities lest they
effect the color of water colors adversly. I have had my poorest results with
premium gums.
The quality of the gum at harvest and from place to place varies.
One filtered batch may vary from another batch depending on *vintage*.
I am not certain that your processing will make a difference, but please
don't let me discourage you. If you are successful in producing good and
consistant gum I will be eternally greatful.
Peace
Al