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.
The Forehead Appears Flat After Blending. You failed to start your work at the highest point of light, or you have not used a light enough stroke in the delicate half-tones around the high-lights. You have probably built up the half-tones equal to the high-lights. This you must not do. Always begin to work at the highest point of light, and gradually blend and model down into the half-tones or shadows, but following the tone of light as you work from the high-lights. Never work up into a high-light from the shadow, as you will invariably build up the shadows too much and thus flatten the features.
Hard Line Between Forehead And Hair. There should be no hard lines at the edge of the forehead, and you should blend into the hair so as to destroy the harsh outline which might exist. It will also be necessary in some negatives to blend a trifle just above the eyebrows. In the majority of cases, however, the flesh near the eyebrows will be soft in appearance and need but very little penciling.
High-Lights Show Too Prominently. You have built up the highest point of light itself and not sufficiently blended around it. It is very seldom necessary to do any work in the extreme highest points of light, as these portions usually are strong enough. Only the spots that appear in the high-lights will need to be removed and blended, but no further building up will be necessary. Should you apply too much lead to any spot in the high-light, you would make this portion denser, and it would then be necessary for you to blend around it, and in doing so you would build up the high-light far too strong as compared to the surrounding tint. Only apply sufficient work to retain the values in the negative, and remember that your work is simply to perfect the original modeling and not to destroy it.
Too Much Contrast Between High-Lights And Shadows. There should be a gradual blending from the high-lights to the shadows, and there should be no abruptness between them. With long general strokes you may easily blend and connect the various
high-lights with the surrounding shadows. If the lights are broken and irregular, due to the shape of the forehead or because of poor lighting, they must be united. If the shadows appear too dense they may be built up somewhat to a higher tone, which will overcome the contrast.
Flesh Effects. If your work does not show a slight grain or flesh effect, your strokes have been made with too much precision. You may have applied too much lead to the negative, or used too short a stroke. Little attention need be paid to the producing of grain, for if you remove the imperfections and blend all portions to their relative tones, you will have secured an excellent flesh effect when your work is completed.