Originally Posted by
paulbarden
Bostick & Sullivan ships their wet plate kits with the silver bath already prepared, in bottles. He won't be mixing his own silver bath, at least this time. But what Kent said is almost guaranteed to be true for you in the future as well: if you make up a silver bath at the recommended rate (9 grams of AgNO3 to 100ml of distilled water) then you will find the specific gravity of the bath is automatically within tolerances of 1.068 to 1.075 (give or take). Not once have a made up a new silver bath and found it to have an SG outside of those values.
Maintaining the specific gravity of the bath does, however, require the purchase of AgNO3 crystals. And as Kent states, handling silver nitrate crystals does require great care: work in a space where nothing/nobody can interrupt what you're doing, wear eye protection, and gloves. If you observe common sense handling precautions, there's nothing to be concerned about. But you don't need to rush out and buy silver nitrate crystals right away: it may take weeks of use before you need to replenish the bath.
A couple of notes regarding the Bostick kit:
- it comes with a small amount of Nitric acid, intended for use to acidify the silver bath. Avoid using this at all, if possible, as it will have the effect of decreasing the speed of your poured plates, and potentially add unwanted contrast. Quinn makes a very clear and compelling case in his book for avoiding the addition of Nitric acid to the bath.
- the kit also includes a small amount of Amino silane bonding agent. AVOID USING IT (All it ever did when I used it was make a mess of the plates and ruin good collodion). It is in the kit to assist you in getting good adhesion of collodion onto glass. If you clean the glass properly and use a 1/8 inch of albumen applied to the edges of the plate (I can demo this for you, if need be) then you will have no difficulty getting the collodion to adhere to the plate. Its not as difficult to get a clean plate as some people think. Quinn's instructions are very clear and he demonstrates it in the videos. Stick to what he recommends and you will avoid most of the problems new practitioners commonly encounter.
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