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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 Excerpt: ... 2 developer is suitable for summer work and for strongly-lighted pictures. The developer should be used sparingly, for the employment of too much solution impairs the brilliancy of the negative.--L. Sternberg. The developer must harmonize with the general use of the light. That is, the same proportions would not answer for an open skylight, or one where the light is subdued by passing through thin curtains, or a ground-glass, or one of a southern exposure. In each one of these the light is of a different value, therefore, the relative proportions of iron, acetic acid, and water must necessarily vary, that harmony may be secured. Iron deposits the silver, acetic acid simply retards. Therefore, it is very essential that these should be in that proportion that accommodates the best use of either of the above-mentioned skylight. Taking a nitrate bath nearly free from alcohol, and an open light, 1 ounce of sulphate of iron to 24 ounces of water, and sufficient acid to cause it to flow quite freely. One ounce will do it. Let this proportion be the thermometer of the bath. When it refuses to flow, do not add more acid, but change the bath. As the plate receives the first lighting under the skylight, so it receives the second under the developer. That is, by the manner of manipulating, it can be made harsh, too intense, streaked and stained, fogged, flat, without detail, too soft, with too much detail; all these, and yet the same can be made just right, in every respect a good negative by the right handling. One cannot consistently be changed without the other, so the bath must be consigned to hotter regions to evaporate. In nine cases out of every ten it will be just at that time when also the excess of iodide needs removing.--G. F. E. Pearsall. A new developing ...
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