Fixing Solution, for Negatives

Hyposulphite of soda, 5 oz., distilled water 5 oz.; dissolve and filter.

Sensitizing Solution, for Paper

Nitrate of silver 5 drs., distilled water 5 oz., nitric acid 2 drops, kaolin 1 oz. Dissolve the nitrate of silver in the water, and then add the acid and kaolin; the kaolin will not dissolve, its use being to prevent the solution becoming discoloured after using. This solution will not require filtering; it must be allowed to become quite clear, and when required for use must be carefully decanted. This solution should be occasionally tested with the argentometer, and sufficient nitrate of silver added to restore it to its original strength.

Another Negative Collodion

Ether 1/2 oz., gun-cotton 7 grs., bromide of cadmium 1/2 gr., bromide of ammonium 1 1/2 grs., iodide of calcium 1 gr., iodide of potassium 1 gr., iodide of ammonium 1 gr. For intensifying, flood with chloride of gold 1 gr., water 15 oz., then wash, and flood with pyrogallic acid 2 grs., water 3 oz.

Toning Baths

1. Chloride of gold 4 grs., acetate of soda 1/4 oz., distilled water 10 oz.; dissolve and filter. 2. To produce black to bright sepia tones, according to length of immersion. Take carbonate of soda sufficient to cover a threepenny piece, dissolve it in a teaspoonful of cold water in a cup, add 2 grs. of chloride of gold, then add 3 oz. of boiling water; use in 15 minutes. This will suit Hart's albuminized paper.

Fixing Solution, for Paper Prints

Hyposulphite of soda 8 oz., distilled water 1 pint. This solution must only be used once.

Stopping-out Negatives

Small, round, transparent spots are frequently found on glass negatives, which, if not stopped, occasion corresponding black spots on the print. Lay the plate on a slab of glass, having either direct or reflected light shining up through it. Then cover the spots with a mixture composed of 10 parts of ivory black, 2 parts of saturated solution of gum arabic, 2 parts of white honey, 1 part of sugar-candy; well mix and apply with a fine camel-hair brush. Should the spots on the negative be black or opaque, white spots will be formed on the print; these are easily tinted with a little water colour, to match the other portions of the print; it is seldom necessary, therefore, to alter the negative on this account.

Ferrotypes

In these, instead of a glass plate being used to receive the picture, as in a positive glass photograph, a thin plate of black varnished iron is employed. Of course, no black backing is required; with this exception the photograph is produced in every particular, by the same means and in the same maimer as the glass positive is.

Various Solutions used in the Dry Process

These are employed in cases where bromo-iodized collodion and the nitrate bath are used. In all processes in which the bromo-iodized collodion is employed, two grains of bromide of cadmium should be added to each ounce of the collodion. Mr. Bartholomew advises diluted alcohol to be poured over the plate previous to developing.

Acid Pyro Developer

This developer is formed as follows:

The plate, after being wetted with dilute alcohol and washed, has this solution flowed over it, to which has been added 2 or 3 drops of a ten-grain nitrate of silver solution.