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.
Attention To Details. It is very essential that the arms and hands receive special attention, even in the making of a bust portrait. The height of the chin, which, to a certain extent, governs the length of the neck and nose, the arranging of the hair, and the direction in which the eyes are turned all require special attention. These points are covered in detail in the following chapter.
212. Lighting the Subject - The angle of light upon the face of the subject is obtained, as previously stated, by placing the subject nearer to, or at greater distance from, the source of light. The height of the window regulates the distance from the light at which the subject should be placed. If the window is extremely high, the light may be lowered by drawing down the top opaque curtain. With a fair sized window, which will permit of working at a little distance from the light, the high-lights should be obtained and accentuated by the direct light coming from the window over the top of the diffusing screen. The object of the diffusing screen is to soften the strong light as it falls upon the subject. As the flood of light grows stronger near the lower part of the window the diffusing screen must be used to diffuse the light from this portion of the window.
213. More than one window - unless close together - should seldom be used; only in extreme cases is it advisable to resort to a divided source of illumination, and, even then, if one is experienced he will be able to produce equally as good results with the one window. As light is required to make a picture, one should use all of it obtainable, bearing in mind, however, that it must be sufficiently controlled to produce the proper effect. For this reason use all of the light admitted through the one window, diffusing only where necessary.
214. If the window is small or low, necessitating the placing of the subject closer to the source of light to obtain proper angle of illumination, you will find quite likely that the high-lights will be rather strong and hard. If they appear too hard soften them with the diffusing screen, by raising or lowering until the proper diffusion is obtained. It is advisable, however, first to obtain the angle of light by the open window before diffusing; second, after placing the subject, to observe the shadow cast by the nose on the shadow side of the face. When this shadow falls slightly below the nose, inclining toward the corner of the mouth, the correct angle, which is about 45°, will have been obtained. (See Illustration No. 13.) Third, see that the highlights are soft. If too hard, soften them by closing the curtain on the diffusing screen. If still too strong, move the subject further from the window, at the same time watching closely the shadow cast by the nose.
215. It is seldom that sufficient softness cannot be obtained with the diffusing curtains, if they have been made of the proper material. If the light is still too strong, rather than move the subject too far away from the light, it would be advisable to place another thickness of cheese-cloth over the diffusing screen. If, with the curtains on the diffusing screen drawn together, the light is too much diffused, by separating them a trifle the high-lights may be strengthened sufficiently to give them the desired snap.
216. The high-lights should be sufficiently strong to leave half-tones visible. You will notice by reference to Illustration No. 14, that more light is admitted from the top of the window than at the bottom. The strongest light always comes from the center of the window, and below. Because of this condition the light from the lower part of the window is softened with the diffusing screen, which, being attached to a cord, permits of its being raised or lowered to soften the lights on the subject where needed.