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.
194. To secure a Broad Profile Lighting the subject is lighted in exactly the same manner as for the front or three-quarter view of the face. The camera, however, is brought around so that it will occupy a position between the subject and the skylight. There may, however, be times when it will be impossible to secure as small an image on the ground-glass as you may desire, for the subject might be seated too close to the light. In this case it will be necessary to move the subject away from the side-light, and raise the shades on the top-light or those on the upper portion of the single-slant light, so that the angle of light may be sufficiently high to give the proper direction.
195. As the shadow cast by the nose is not seen in a profile lighting, it is not so objectionable if the light does fall rather over-abundantly from the side; however, carried to the extreme, the effect produced will be flat, and the prominences on the face will not stand out in their relative values, nor will the eye appear properly illuminated.
196. Do not forget to place the background properly, as it is essential to have a little more of the ground to the front of the subject than to the back. In Profile Lightings, as the subject faces directly toward the margin of the print, more space must be left on the finished portrait to the front than at the rear, in order to supply distance into which the subject appears to look.
197. The light, of course, should not be harsh. On the contrary, it must be soft and diffused, as a harsh light will destroy the delicate half-tones, while a diffused light preserves them. Practically no reflected light will be required. In fact, if the diffusing curtains have been used judiciously it will be quite unnecessary to employ reflected light.