Pyrogallic acid                    4 grammes. 
Metabisulphite of potassium        11/2   "
Water                            100 c. c.

This solution keeps for weeks in corked bottles.

  B.

Crystallized soda                 10 grammes. 
Neutral sulphite of soda          15    "
Water                            100 c. c.

Before using mix—­

Pyro solution A                   20 c. c. 
Soda solution B                   20  "
Water                             20  "

The developer acts about one and a half times slower than the ordinary pyro soda developer, approaching to the latter pretty nearly, and gives to the negatives an agreeable color and softness, with clear shadows.  If the negatives are to be thinner, more water, say 30 to 40 c. c., is taken.  If denser, then the soda is increased, and the water in the developer is reduced.  An alum bath before fixing is to be recommended.

An advantage of this development is the great durability of the pyro-meta sulphite solution.  The cost price is about the same as that of the ordinary pyro developer.  At all events, it is worth while to make further investigation with the metabisulphite of potassium, the same being also a good preservative for hydroquinone solutions.—­Photographische Correspondenz; Reported in the Photo.  News.

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