> > I first spray painted them, now I don't darken them and get better
> > results. Does selenium work on brass?
>
> Selenium not so well. Try different toners. Maybe polysulfides? There
> are ways of blackening brass but I cannot recall them offhand. Check out
> literature on electroplating, also possibly sources of formulas for
> patina. Selenium works great on copper. Brass is actually not
> consistent, one sample to another. It is usually alloy of copper and
> zinc. There are lots of different brasses so generalizations are not
> possible.
The formula below could be dangerous. If I were to use them I would
use a fume hood and wear goggles. I have not tried any of the methods
below and pass them on out of historical interest.
--greg schmitz
The following is from:
Wall and Jordan. PHOTOGRAPHIC FACTS & FORMULAS. Boston: American
Photographic Publishing Co., 1940.
TO BLACKEN BRASS. -
Copper nitrate 208 g.
Water 500 cc
Dissolve and add the following solution:
Silver nitrate 208 g.
Water 500 cc
Clean the metal thoroughly, immerse in the mixture, and then heat;
repeat if necessary.
Another method is to immerse in the following:
Copper carbonate 50 g.
Ammonia 25 cc
Water 1000cc
Clean the metal and immerse until black, then wipe dry and lacquer.
This attacks soft solder. Solution of antimony chloride (butter of
antimony), brushed on, gives bronze colors. Boiling the metal in a
solution of potassium sulphide (liver of sulphur) until sufficiently
black, then rinsing, drying, and smearing a little oil over it, gives
better results than the above silver method.
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>===for PGP Key finger Greg Schmitz <gws1@cunix.cc.columbia.edu>===
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Key fingerprint = 73 D3 91 15 96 69 74 E5 14 51 71 44 C8 ED 01 11
Key ID: A7026B1D Key Size: 1024 bits Created: 1994/11/10
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