From: Sandy King (sanking@clemson.edu)
Date: 07/23/03-09:14:11 PM Z
Kathrine Thayer wrote:
>Sandy looked at the amount
>of dichromate in relation to the amount of gum and called it 20% and
>said that was less than saturated ammonium dichromate and asked why are
>so many gum printers using more dichromate than is necessary?
Not exactly. I assumed, and so stated in the message to which you
allude, that the addition of pigment (assuming pigment in liquid
dispersion, though not specified) would reduce slightly the amount of
dichromate in relation to the total quantity of emulsion to less than
20% The 16% solution that you derive is very close to what I would
have predicted.
>
>The thing is, we generally don't calculate the dichromate percentage
>that way, as the amount of dichromate relative to the amount of gum. We
>generally calculate it as the amount of dichromate relative to the
>amount of water, and we add that solution to the gum but don't add the
>gum to how we're figuring the percentage of dichromate.
Do you not figure the amount of pigment in the calculation.
Sandy King
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