The lighting of the exposition can barely be touched upon in a few paragraphs and it would be difficult to describe in words even if space were unlimited.  It represented the power of light to beautify and to awe.  It showed the feebleness of the decorator’s media in comparison with light pulsating with life.  It consisted of a great variety of direct, masked, concealed, and projected effects, but these were blended harmoniously with one another and with the decorative and architectural details of the structures.  It was a crowning achievement of a century of public lighting which began with Murdock’s initial display of a hundred flickering gas-jets.  It demonstrated the powers of science in the production of light and of genius and imagination in the utilization of light.  It was a silent but pulsating display of grandeur dwarfing into insignificance the aurora borealis in its most resplendent moments.

XXIII

THE EXPRESSIVENESS OF LIGHT

From an esthetic or, more broadly, a psychological point of view no medium rivals light in expressiveness.  Not only is light allied with man’s most important sense but throughout long ages of associations and uses mankind has bestowed upon it many attributes.  In fact, it is possible that light, color, and darkness possess certain fundamentally innate powers; at least, they have acquired expressive and impressive powers through the many associations in mythology, religion, nature, and common usage.  Besides these attributes, light possesses a great advantage over the media of decoration in obtaining brightness and color effects.  For example, the landscape artist cannot reproduce the range of values or brightnesses in most of nature’s scenes, for if black is used to represent a deep shadow, white is not bright enough to represent the value of the sky.  In fact, the range of brightnesses represented by the deep shadow and the sky extends far beyond the range represented by black and white pigments.  The extreme contrast ordinarily available by means of artist’s colors is about thirty to one, but the sky is a thousand times brighter than a shadow, a sunlit cloud is thousands of times brighter than the deep shadows of woods, and the sun is millions of times brighter than the shadows in a landscape.

The range of brightnesses obtainable by means of light extends from darkness or black throughout the range represented by pigments under equal illumination and beyond these through the enormous range obtainable by unequal illumination of surfaces to the brightnesses of the light-sources themselves.  In the matter of purity of colors, light surpasses reflecting media, for it is easy to obtain approximately pure hues by means of light and to obtain pure spectral hues by resorting to the spectrum of light.  It is impossible to obtain pure hues by means of pigments or of other reflecting media.  These advantages of light are