Artificial Lighting

135. In considering artificial light, we will avoid all efforts to analyze the different forms of energy, magnetic energy, electric energy, heat energy, mechanical momentum, radiating energy, and deal with result rather than with cause and effect. It will be sufficient to state as the deduction of the scientist that certain waves or vibrations which affect the fibers of the optic nerve are transmitted by the brain into color. Self-luminous bodies are bodies which produce light. Illumin

ted bodies shine by borrowed light, and are distinguished by the different amounts and quantities of light which they reflect. A dense cloud which appears nearly black when between the observer’s eye and the sun, owing to the degree of density with which it intercepts the light, may become brilliantly white when the sun’s rays fall upon its constituent particles, for the light which cannot penetrate the cloud is continually reflected to and from the surface of its minute parts. Thus it happens that the lower part of a cloud seen against a background of dark mountain may appear white, while the upper part may appear dull gray. In the alteration of reflection we have an alteration of color. A stick of sealing wax will show in some positions white reflected light, while in other positions we see only the red. A polished plane furnishes one kind of reflection, a piece of chalk another.

136. The decorator has for years past been disposed to defer to the illuminating engineer in the artificial lighting of a home. But while the technical man or engineer may have a knowledge of power and energy, he has not studied the decorative value of lighting. His problem has been economic rather than psychologic. The illuminating engineer cannot be expected to appreciate fully the harmonies of color in decoration.

137. It is the decorator’s province to consider not only the power of light in the furnishing of a house, but the character of the light—not only its color influence, but the structural character of its introduction, as affecting these furnishings. It is beyond his province to determine whether carbon should be replaced by tantalum, osmium or tungsten to get higher efficiency, but he must understand the effects of these lights and prescribe accordingly.