This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Normal Exposure. To illustrate this subject clearly, we have selected a landscape scene, containing not only the extremes of high-lights and shadows, but all of the intermediate tones, and practically every degree of gradation. In this particular picture the road is composed of white limestone, which, in those portions receiving the direct rays of the sun, reproduces perfectly white. The opposite extreme will be found in the shadow of the tree trunks, where there is a trifle detail, yet the negative in this portion is practically clear. The bushes and the small trees on the further side of the fence give any amount of tones; while the shadows cast on the road by the branches of the trees are sufficiently strong to demonstrate the errors which are very likely to occur upon development.
315. In Illustration No. 33 is illustrated the positive print made from a normal negative, and in Illustration No. 34 the negative is shown. Compare these two illustrations - the positive and negative. Both should be studied carefully before proceeding further.
316. The development of this correctly exposed negative, as shown in Illustration No. 34, has been carried just far enough, in that the highest points of light, which are the high-lights on the road and the light from the sky showing through the branches of the trees, have been developed so that they are almost opaque.
317. One great difficulty in working with subjects of this kind is the tendency of the sky (which quickly acts upon the sensitive plate) to become over-developed (hence very opaque) by the time the high-lights of the balance of the picture are carried to the proper stage in development. If the negative has been under-developed (not left in the developing solution long enough) the high-lights will be weak, and the shadows will not contain as much detail as is required.
318. The over-development of normal exposures very seldom increases the amount of detail in the shadows, and in the majority of cases simply tends to cause a fog of the deeper shadows.
320. An under-developed over-exposure gives a weak, flat negative. To correctly develop an over-exposure the development, unless it can be restrained in time to overcome the flatness, should be carried a trifle further than is required to produce a correctly developed, normally exposed negative. (See Illustration No. 36.)
Illustration No. 35Print from Over Exposed Though Correctly Developed Negative.
See Paragraph No. 319
Illustration No. 36A Correctly Developed, Over-Exposed Negative.
See Paragraph No. 320
Illustration No. 37Print from Under-Exposed and Correctly Developed Negative.
See Paragraph No. 323
Illustration No. 38An Under-Exposed, Correctly Developed Negative.
See Paragraph No. 324
Appearance of Negatives with Different Exposures. 185 tive which has been over-exposed and slightly over-developed can be reduced in a reducing solution, which will not only reduce the entire plate but will clear the high-lights and shadows as well, thus giving them snap - resulting in a good printing negative. Therefore, by proceeding to handle an over-exposure in this manner, it is possible to correct the error of over-exposure and secure a negative which very closely resembles the normal negative. The greatest fault with the average worker in handling over-exposed negatives is to under-develop them, as he thinks that the fogging over during the early part of the process of development signifies that sufficient density has been secured.
322. There is, however, a possibility of over-developing an over-exposure. When carried to this extreme, the shadows are usually veiled with a heavy fog, and the negative is practically ruined, unless given a vigorous treatment with the proper reducer and afterwards intensified. Whenever possible one should try and restrain an over-exposure during development, and thus avoid the necessity of overdeveloping.