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The Barnet Book of Photography A Collection of Practical Articles

Mix equal parts of ortol solution and soda solution

SODA SOLUTION. Sodium carbonate, crystallised. 1 oz. or 10 parts Sodium Sulphite 1 oz. or 10 parts Potassium bromide 10 grains or 0.23 part Water to make up to[3] 10 oz. or 100 parts

[2] No more of the dilute pyro solution should be made up than is likely to be used during the same day, but it will keep well enough for a day or two.

[3] The sodium sulphite and carbonate are dissolved, with the aid of heat, in about 8 oz. (80 parts) of water, the bromide added, and the liquid when cold made up to 10 oz. by adding water.

For use mix equal parts of dilute pyro solution and soda solution and pour over the plate.

If the exposure has been correct the image will begin to appear in about a minute, and development is then allowed to go on with occasional rocking of the dish, until the negative is sufficiently opaque.

If the plate behaves as if it were under-exposed, _at once_ dilute the developer with an equal bulk of water and pour it back over the plate. If the high-lights continue to increase in opacity, but the rest of the image does not appear, add some more of the soda solution with or without some more water. Should parts of the plate still remain blank, apply some of the soda solution to them

with the aid of a brush as described under pyro-ammonia (page 32).

If the rapid appearance of the image indicates that the plate is over-exposed, at once pour off the developer into a measure or mixing glass and rinse the plate well with water. Add to the developer a small quantity of potassium bromide solution (1 in 10 of water) which should be kept at hand for this purpose. A small quantity of pyro stock solution may also be added. The developer is then poured over the plate again. When the over-exposure seems to have been considerable, the amount of potassium bromide added may amount to 4 grains (or 40 minims of the 1 in 10 solution) per ounce of the developer, but this proportion should not be exceeded; even small quantities of bromide in the pyro-soda developer have a marked influence in retarding development.

When there is reason to suspect over-exposure, not more than half the soda solution should be added at the beginning of development, and the rest may be added or not, as the case may require.



Ortol 130 grains or 1.5 parts Potassium metabisulphite[4] 65 grains or 0.75 part Water to make up to 20 ounces or 100 parts

SODA SOLUTION. The same as for pyro-soda.

[4] See foot-note to page 30.

Mix equal parts of ortol solution and soda solution.

This developer behaves in much the same way as pyro-soda and gives very similar results. It has the advantage, however, that it does not stain the fingers, and has practically no tendency to produce either fog or stain on the plates. Moreover the same quantity of solution can be used for several plates; when the action becomes perceptibly slower or weaker, part of the old solution is poured away and an equal quantity of freshly mixed ortol and soda solutions is added.

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