CHAP. VI.

THE DAGUERREOTYPE PROCESS.

The process of taking Daguerreotype pictures differs very materially
from all others of the photographic art, inasmuch as the production
of the image is effected upon plates of copper coated with silver.
The silver employed should be as pure as possible; the thickness of the plate
is of little consequence, provided there be sufficient silver to bear
the cleaning and polishing--is free from copper spots, is susceptible
of a high polish, an exquisitely sensitive coating and a pleasing tone.
These qualities are possessed to an eminent degree by the French plates.

Having already enumerated the various processes--and the apparatus
necessary for the manipulation, I will here give a list of the
chemicals to be used, and then proceed to explain them more fully.
The requisite chemicals are--

NITRIC ACID, ROUGE,
DRY IODINE, MERCURY,
DRYING POWDER, HYPOSULPHITE OF SODA,
CYANIDE OF POTASSIUM, CHLORIDE OF GOLD; OR
ROTTENSTONE, HYPOSULPHITE OF GOLD.
TRIPOLI, CHLORIDE OF SILVER.
CHLORIDE OF IODINE, } their compounds, or other
BROMINE } accelerating mixtures.

FIRST OPERATION.--Cleaning and polishing the plate.--