American cinematographer (Feb-Dec 1922)

March I. 1922 THE AMERICAN CINEMATOGRAPHER L3 Light and Its Effective Properties In Photography First Installment of "The Science of Creative and Construfiive Photography" By Eugene B. Downing JN this article Mr. Downing lays the foundation for his second paper. "Camera Exposure and the Working Latitude of Motion Picture Negative Film," which will appear in the April number of The American Cinematograph kr. In view of the fact that the basic and fundamental principles of photography are herein approached from a radically new angle and peculiar point of view, in some respects quite contrary to the generally accepted theories of common practice, some considerable time must be given up to clarify properly the basis of reason and calculation. The hypothesis from which the following deductions evolved was from the assumption, that creative and constructive processes co-essential to photography pertain to a branch of exact science and that it conformed to certain laws of evolution with positive regularity and mathematical certainty. If this be true we then reason as follows: Every science has for its base a system of principles as fixed *and unalterable as those by which the universe is regulated and governed. Man cannot make principles but he can discover them and thereafter he can apply them practically to his own good. Photo-chemical processes are truly by nature creative and constructive. The term creative confirms the existence of some basic element, force or factor of cause. The term constructive at once gives suggestion of a product having attributes of form, dimensions, proportions, or specific characteristic, constituting values of architectural effect. We cannot contemplate constructive photography from a basis of analysis without means of measure or mathematical formula, as only by the aid of mathematics can analysis obtain and convey to our understanding a sense of relative proportions and definite equivalents which exist between the authority of cause and its product as manifest in effect. Therefore of first necessity is to adopt a practical means of mathematical calculation. For this essential requisite we will establish as our base a definite standard of smallest worth, a portion (not subject to division or fractional consideration) a denominate unit, as a minimum value. By virtue of this definite standard other and greater values may be relatively and definitely known. As a means to calculate the value of cause relative to effect, the unit method is more readily adaptable and comprehensive for this purpose. A unit measure is a measure analagous to a given purpose. It is the smallest measure of specific value to the purpose for which it is used. The unit measure of light energy, element or substance, latent or visible, as applied to photography, is based upon its effective intrinsic worth to the purpose for which it is used. In contemplating the characteristic and peculiar properties of light, it is well to consider its true values by law of polarity. Light is a positive vital energy — its negative or opposite is darkness. Light and darkness are completely opposed to each other and give ocular impressions as distinct as two extremely opposed ideas could give to the mind. However, they admit of intermediate degrees of expression. Equadistant from each is neutrality or the middle — fiftyfifty. It is a value, impression, or effect of definite and intrinsic worth. Its position is unalterable, being fixed positively relative to and corresponding to both. In photography values of cause-energy are calibrated from a basis of their relative and corresponding products constituting the attributes of effect. In picture making by the process of photography, the first prime factor of cause is energy. This causeenergy exists within light. It is a peculiar property of light and for our purpose may be known as Latent Energy of Reduction. It is invisible to the eye and therefore quite difficult to conceive of its true existence. However, if we may term it the Spawn of Light, this term may help us to visualize and individualize its actuality. By camera exposure, this energy, or spawn of light, is deposited within the sensitive film. Therein it finds certain friendly affinities and comes to rest in a latent state, inactive, invisible, but nevertheless it is there. These energy deposits, when given the opportunity bv subjection to a developing solution, will manifest the measure of their vito-active values by self conversion to a state of metallic silver substance. The process of transformation from invisible energy to metallic substance is not spontaneous or erratic; it conforms to the harmonious law of evolution or growth. Its rapidity of materialization is analogous to and co-relative to the volume of intensity of light from which this property of energy was taken. Equation of unlike but relative and corresponding values is the problem of photo-chemical operations. When a combination of value differences are taken collectively for purposes of effect, the basis of true values are visible, perceptible differences, which give effects or distinct ocular impressions. Therefore the effects or impressions are greater and lesser, limited to the number of contrast or dimensional differences of expression. Uninterrupted light is without form, figure or fashion. When the velocity of light is interrupted by an object of shapely mass or dimensional form, the reflected consequence is a dispersement of multi-quantity differences. This fractional product is effective relative to locale and incidence of deflection and light thus deflected in a consequence of individualized specific valueand has mathematical form of expression. Therefore light is our model. Light as deflected from the object photographed. By camera exposure a film is impregnated with greater and lesser deposits of latent energy as dispensed from the leflective surfaces of the object. The differential ratio or scale of energy deposits, by mathematical