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.
Eyes Of Subject Appear Staring. This difficulty is frequently caused by the subject gazing too long at the same object during the preliminaries of posing and lighting. The person may also be near-sighted, and the object at which the eyes are looking may be too far away. To surmount this difficulty, carefully follow these instructions. Watch the subject carefully, and by standing closer to or further from the subject, while they are looking at you, or by placing the eye rest at various points, you will soon observe the proper distance that will permit the eyes to rest naturally. Also permit the subject to wink as often as desired during the exposure. It is not advisable to have them look at the small object on the pole, but simply in that direction, for to raise the eyes up or down, or from side to side, during the exposure, would cause the pupil of the eye to become blurred. It is not advisable to tell the subject just where you wish them to look until you are ready to make the exposure.
Closing Of Lips Too Tightly. Never tell the subject to close the mouth or to open it; rather converse with them - get them to answer some questions, or finally suggest that they pass the tongue over the lips, to moisten them. The mouth will then assume a natural expression, and the exposure should be made instantly, before the mouth begins to twitch. Under such circumstances the subject should not know when the exposure is being made.
Plate Developing Contrasty. This is either because the lighting was too contrasty - too strong a light causing deep shadows - or the plate was under-exposed. Light the subject so there will be even gradation from the highest lights to the deepest shadows. In making an exposure, time for the deepest shadows. Rather over than under-expose. In this way the difficulty can be overcome. A diluted developer is best for contrasty lightings, but the best plan is to light the subject exactly according to the result desired in the finished picture.
Plate Developing Flat. This is the reverse condition to plate developing contrasty. In this case it is caused either by flat lighting of the subject or extreme over-exposure. Aim to secure proper lighting and exposure, and in either case treat the plate in development according to its exposure.