Various recipes for patination embossed metals

PURPLE COLORING OF YELLOW COPPER.
To make brass take on a beautiful purple shade, simply heat it uniformly and strongly enough so that it can barely be held in the hand and rub it with a cotton pad impregnated with antimony chloride.
(Scientific Monitor, 1860.)

PLATINUM TONE ON COPPER.
To give copper the appearance of platinum, simply immerse the objects to be patinated in a solution of:
Arsenious acid……... 35 gr.
Copper acetate……… 6 gr
Water…………………….. 200 ml
The shade obtained is a metallic gray a little darker than the true shade of platinum.

BROWN PATINAS OF YELLOW COPPER.
A pale brown is obtained by short immersion in a boiling liquor composed of 8 grams of copper sulfate, 2 grams of ammonia hydrochloride and 100 grams of water. The objects must be removed quickly, otherwise the brown will turn red.
A darker brown is given by covering, using a brush, the heated metal (until the water sizzles on contact) with a layer of liquor composed as follows: dissolve 5 grams of acidic copper acetate and 5 grams of ammonia hydrochloride in a liter of water; let it sit for a few hours and add a liter of water.
(Laboratoire de la Nature, 1912.)

HOW COPPER IS BLACKENED.
Take some oil made from linseed; with your finger, apply a thin layer everywhere, level it with a goose feather, and, holding it with pliers, place it on hot coals. When it is heated, you will oil it again with a pen and put it back on the coals... If it is not black enough, you will start again. You will let the piece cool not in the water, but by itself.
THEOPHILE (12th century).

MOIREAGE OF YELLOW COPPER.
Immerse the objects to be moiré, with a few old nails, in a boiling bath of:
Copper sulfate…….. 250 gr.
Water……………………… 500 ml
The color appears after a few moments of immersion.
(Science Illustrée, 1902.)