Re: Van Dyke- Increasing contrast

Bas van Velzen (eland@knoware.nl)
Tue, 18 Jun 1996 18:43:21 +0100

>Bleach print in 5 gms mercuric chloride,
> .5 gms pot bromide (That's 1/2 gm)
> 1000 mls water.
>
>The proportions don't seem to matter much, I used to eyeball it out. The
>above is from memory.
>
>Wash in 3 baths of 5% hydrochloric acid for 5 minutes. It'll stain if you don't
>
>Wash for 5 minutes
>
>Re-develop in Dektol (that's right!)

I don't think mercury is more stable than silver since it is lower in the
precious metals list

K Ba Ca Na Mg Al Zn Fe Ni Sn Pb | Cu Hg | Ag Pt Au

< non precious metals semi precious precious metals >

Not a chemist and looking up solubility parameters of salts in water it
looks like silversalts are slightly less soluble than mercury salts.
I guess that pot bromide is a strong sedative. I know bromide is used in
tranquilisers so this must be extra strong. What is the name of the plant
you can get it from?

Bas

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