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 Principal Object Of Interest. Another vital point in composition is: There must be a principal object of interest in the picture, and that object must be put in the right place, not only with regard to the spacing of the negative, but also in relationship to the other details of the picture. For this
Illustration No. 30 purpose you will find it an excellent plan to rule your ground-glass in the manner indicated on the accompanying diagram (see Illustration No. 30.) The crosses indicate the positions of strength; the weakest part of the space is the center. The principal object of the picture, therefore, should be placed very close to where the lines intersect; that is to say, near, but not in, the middle of the picture. Of the two sides the left is stronger than the right. Therefore, a picture having its most important masses on the left side is, as a rule, more satisfactory than when the reverse is the case. You can see this very readily by selecting a negative which is "one sided" and comparing the effects produced by viewing it; first, holding the film side toward you, then turning it around and viewing from the glass side.
Subordination. Having secured a principal object in the picture space and placed it in proper position, it is necessary to next consider the placing of the remaining subjects or points of interest. In other words, it is necessary to so handle the various items in the picture space that the principal object will stand out in greatest prominence, all other portions being subordinate - the eye must not be distracted by counter attractions in other parts of the picture. You will, no doubt, find this principle the most difficult one to carry out, for it not only involves a knowledge of composition and an ability to employ this knowledge in your actual work, but also the exercise of proper treatment in the developing and printing of the photograph, whereby certain details can be suppressed and others strengthened.
Harmony. Each picture must present a harmonious whole, and there must be no intrusion of details that stand out in the picture to destroy the original idea. This principle is very easily violated by introducing unsuitable figures into the landscape. If figures are introduced into the scene their dress and general appearance must conform to the idea that you intend to convey in the view. If the preceding principles have been carefully carried out, this Law of Harmony will, practically speaking, have been taken care of.
Balance. The final, and perhaps the most vital, point for consideration is the Law of Balance, or the filling up of the picture space. Above all things the unity of the picture is of the greatest importance, and it is very necessary to secure this unity, or balance, on the ground-glass of the camera, and thus have it in the resulting negative. It is possible, however, if the correct balance is not secured in the negative, to trim the resulting print (see Trimming and Mounting, Volume IV), which will help wonderfully. If, however, the correct distribution of the masses can be obtained without trimming, the general effect will be much better.