On 11 June Judy wrote:
Terry, you seem to be answering the wrong question about the
Baume. Jeff is saying that the higher numbers are thinner solutions.
You're saying that they're thicker. One of you is probably wrong.... I'll
add, BTW, that my nice RBP gum is heavier, tho still labelled 14 baume, so
go figure....
I had said:
> As to Baume, my Chambers says that it a measure of the speciic gravity of
> liquids where 0 degrees is the weight of water at 20 C and 10 degrees is the
> weight of a 10 % solution of sodium chloride.
The implication of that is that degrees Baume are a measure of the specific
gravity of heavy liquids. I had assumed that, where viscous liquids are
concerned, increased weight per ml tended towards increased viscosity. I took
this as no more than a rough guide certainly not as a proven scientific fact.
As small changes in the viscosity of a gum can have significant effects on its
performance, is there a measure of viscosity that might more appropriately used
in our discussions ?
The significance related to my own experience is that I find that 17 Baume gums,
the W & N and Gloy and slightly heavier gums such as gum arabic powder mixed as
a fifty percent solution, work well for me giving very little risk of
degradation in the highlights even with unsized papers. I find that others use
14 Baume gums or dilute their 17 Baume gum with water but I understand that they
are working with hardened substrates.
This only tends to confirm that gum is a very forgiving medium.
Terry King