In the preceding chapters the progress of light has been sketched from its obscure infancy to its vigorous youth of the present time. It has been seen that progress was slow until the beginning of the nineteenth century, after which it began to gain momentum until the present century has witnessed tremendous advances. Until the latter part of the nineteenth century artificial light was considered an expensive utility, but as modern lamps appeared which supplied adequate light at reasonable cost attention began to be centered upon utilization, and the lighting engineer was born. Gradually it is being realized that artificial light is no longer a luxury, that it may be used in great quantity, and that it may be directed, diffused, and altered in color as desired. Although the potentiality of light has been barely drawn upon, the present usages surpass the most extravagant dreams of civilized beings a half-century ago. Mere light of that time was changed into more light as gas-lighting developed, and more light has increased to adequate light of the present time through the work of scientists.

It is apparent that a sudden enforced reversion to the primitive flames of fifty years ago would paralyze many activities. Much of interest and beauty would be blotted out of this brilliant, pulsating, productive age. It is startling to note that almost the entire progress in artificial lighting has taken place during the past hundred years and that most of it has been crowded into the latter part of this period. In fact, its development since it began in earnest has gone forward with ever-increasing momentum. On viewing the wonders of modern artificial lighting on every hand it is not difficult to muster the courage necessary to venture into its future.

The lighting engineer has been a natural evolution of the present age, for the economic aspects of lighting have demanded attention. He is increasing the safety, efficiency, and happiness of mankind and civilization is beginning to feel his influence economically. However, with the advent of adequate, efficient, and controllable light, the potentiality of light as an artistic medium may be drawn upon and the lighting artist with a deep insight into the possibilities of artificial light now has his opportunity. But the artist who believes that a new art may be evolved to perfection in a few years is doomed to disappointment, for it is necessary only to view retrospectively such arts as painting and music to be convinced that understanding and appreciation develop slowly through centuries of experiment and contact.

Will lighting ever become a fine art? Will it ever be able alone to arouse emotional man as do the fine arts? Are the powers of light sufficiently great to enthrall mankind without the aid of form, music, action, or spoken words? It is safer to answer "yes" than "no" to these questions. Painting has reached a high place as an art and this art is the expressiveness of secondary or reflected light reinforced by imitation forms, which by a combination of light and drawing comprise the "subjects." A painting is a momentary expression of light, a cross-section of something mobile, such as nature, thought, or action. Light has the essential qualifications of painting with the advantages of a greater range of brightness, of greater purity of colors, and the great potentiality of mobility. If lighting becomes a fine art it will doubtless be related to painting somewhat in the same manner that architecture is akin to sculpture. With the introduction of mobility it will borrow something from the arts of succession and especially from music.

The art of lighting in its present infancy is leaning upon established arts, just as the infant learns to walk alone by first depending upon support. The use of color in painting developed slowly, being supported for centuries by the strength of drawing or subject. The landscapes of a century ago were dull, for color was employed hesitatingly and sparingly. The colors in the portraits of the past merely represented the gorgeous dress of bygone days. But the painter of the present shows that color is beginning to be used for itself and that the painter is no longer hesitant concerning its power to go hand in hand with drawing. Drafting and coloring are now in partnership, the former having given up guardianship when the latter reached maturity.

Lighting is now an accompaniment of the drama, of the dance, of architecture, of decoration, and of music. It has been a background or a part of the "atmosphere" excepting occasionally when some one with imagination and daring has given it the leading rÔle. Even in its infancy it has on occasions performed admirably almost without any aid. The bursting rocket, the marvelous effects at the Panama-Pacific Exposition, and some of the exhibitions on the theatrical stage are glimpses of the potentiality of light. To fall back upon the terminology of music, these may be glimmerings of light-symphonies.

Harmony is simultaneity and a painting in this respect is a chord—a momentary expression fixed in material media. A melody of light requires succession just as the melody in music. The restless colors of the opal comprise a light melody like the songs of birds. The gorgeous splendor of the sunset compares in magnitude and in its various moods with the symphony orchestra and its powers. Throughout nature are to be found gentle chords, beautiful melodies and powerful symphonies of light and this music of light exhibits the complexity and structure analogous to music. There is no physical relation between music, poetry, and light, but it is easy to lean upon the established terminology for purposes of discussion. Those who would build color-music identical to sound music are making the mistake of starting with a physical foundation instead of basing the art of light-expression upon psychological effects of light. In other words, a relation between light and music can exist only in the psychological realm.

These melodies and symphonies of light in nature are admittedly pleasing or impressive as the case may be, but are they as appealing as music, poetry, painting, or sculpture? The consensus of opinion of a large group of average persons might indicate a negative reply, but the combined opinion of this group is not so valuable as the opinion of a colorist or of an artist who has sensed the wonders of light. The unprejudiced opinion of artists is that light is a powerfully expressive and impressive medium. The psychologist will likely state that the emotive value of light or color is not comparable to the appeal of an excellent dinner or of many other commonplace things. But he has experimented only with single colors or with simple patterns and his subjects are selected more or less at random from the multitude. What would be his conclusion if he examined painters and others who have developed their sensibilities to a deep appreciation of light and color? It is certain that the painter who picks up a purple petal fallen from a rose and places it upon a green leaf is as thrilled by the powerful vibrant color-chord as the musician who hears an exquisite harmony of sounds.

Music has been presented to civilized mankind in an organized manner for ages and the fundamental physical basis of modern music is a thousand years old. Would the primitive savage appreciate the modern symphony orchestra? Even the majority of civilized beings prefer the modern ragtime or jazz to the exquisite art of the symphony. An appreciation of the opera and the symphony is reached by educational methods extending over long periods. An appreciation of the expressiveness of light cannot be expected to be realized by any short-cut. Most persons to-day enjoy the melodramatic "movie" more than the drama and relatively few experience the deep appeal of the fine arts. Surely the symphony of light cannot be justly condemned because of a lack of appreciation and understanding of it, for it has not been introduced to the public. Furthermore, the expressiveness of music is still indefinite at best despite the many centuries of experimenting on the part of musicians.

If poetry is to be believed, the symphonies of light as rendered by nature in the sunsets, in the aurora borealis, and in other sky-effects of great magnitude have deeply impressed the poet. If his descriptions are to be accepted at their face-value, the melodies of light rendered in the precious stone, in the ice-crystal, and in the iridescence of bird-plumage please his finer sensibilities. If he is sincere, mobile light is a seductive agency.

The painter has contributed little of direct value in developing the music of light. He is concerned with an instantaneous expression. He waits for it patiently and, while waiting, learns to appreciate the fickleness of mood in nature, but when he fixes one of these moods he has contributed very little to the art of mobile light. Unfortunately the art schools teach the student little or nothing pertaining to color for color's sake. When the student is capable of drawing fairly well and is acquainted with a few stereotyped principles of color-harmony he is sent forth to follow in the footsteps of past masters. He may be seen at the art museum faithfully copying a famous painting or out in the fields stalking a tree with the hopes of an embryo Corot. The world moves and has only a position in the rank and file for imitators. Occasionally an artist goes to work with a vim and indulges in research, thereby demonstrating originality in two respects. Painting is just as much a field for research as light-production.

Recently experiments are being made in the production of color-harmonies devoid of form. Surely there is a field for pure color-composition and this the field of the painter which leads toward the art of mobile light. Many of the formless paintings of the present day which pass under the banner of this ism or that are merely experiments in the expressiveness of light. Being formless, they are devoid of subject in the ordinary sense and cannot be more or less than a fixed expression of light. Naturally they have received much criticism and have been ridiculed, but they can expect nothing else until they are understood. They cannot be understood until mankind learns their language and then they must be understandable. In other words, there are impostors gathered around the sincere research-artist because the former have neither the ability to paint for a living nor the inclination to forsake the comparative safety of the mystery of art for the practical world where their measure would be quickly taken. This army of camp-followers will not advance the art of mobile light, but the sincere seekers after the principles of light-expression who form the foundation of the various isms may contribute much.

The painter will always be available with his finer sensibility to appreciate and to aid in developing the art of mobile light, but his direct contribution appears most likely to come from the present chaos of experiments in pure color-composition, in the psychology of light, or, more broadly, in the expressiveness of light. The decorator and the designer of gowns and costumes do not arrogate to themselves the name "artist," but they are daily creating something which is leading toward a fuller appreciation of the expressiveness of light. If they do not contribute directly to the development of the art of mobile light, they are at least aiding in developing what may eventually be an appreciative public.

The artist paints a "still-life," the decorator creates a color-harmony of abstract or conventional forms, and the costumer produces a color-composition in textiles. The decorator and costumer approach closer to pure color-composition than the artist in his still-life. The latter is a grouping of objects primarily for their color-notes. Why bother with a banana when a yellow-note is desired? Why utilize the abstract or conventional forms of the decorator? Why not follow this lead further to the less definite forms employed by the costumer? Why not eliminate form even more completely? This is an important point and an interesting lead, for to become rid of form has been one of the perplexing problems encountered by those who have dreamed of an art of mobile light.

The painter who uses line and color imitatively has perhaps acquired skill in depicting objects and more or less appreciation of the beautiful. But if he is to be creative and to produce a higher art he must be able to use line and color without reference to objects. He thus may aid in the development of an abstract art which is the higher art and at the same time aid in educating the public to appreciate pure color-harmonies. From these momentary expressions of light and from the experience gained, the mobile colorist would receive material aid and his productions would be viewed by a more receptive audience or rather "optience" as it may be called. The development of taste for abstract art is needed in order that the art of mobile light may develop and, incidentally, an appreciation of the abstract in art is needed in all arts.

Science has contributed much by way of clearing the decks. It has produced the light-sources and the apparatus for controlling light. It has analyzed the physical aspects of color-mixture and has accumulated extensive data pertaining to color-vision. It has pointed out pitfalls and during recent years has been delving further by investigating the psychology of light and color. The latter field is looked to for valuable information, but, after all, there is one way of making progress in the absence of data and that is to make attempts at the production of impressive effects of mobile light. Some of these have been made, but unfortunately they have been heralded as finished products.

Perhaps the most general mistake made is in relating sounds and colors by stressing a mere analogy too far. Notwithstanding the vibratory nature of the propagation of sound and light, this is no reason for stressing a helpful analogy. After all it is the psychological effect that is of importance and it is absurd to attribute any connection between light-waves and sound-waves based upon a relation of physical quantities. No space will be given to such a relation because it is so absurdly superficial; however, the language of music will be borrowed with the understanding that no relation is assumed.A few facts pertaining to vision will indicate the trend of developments necessary in the presentation of mobile light. The visual process synthesizes colors and at this point departs widely from the auditory process. The sensation of white may be due to the synthesis of all the spectral colors in the proportions in which they exist in noon sunlight or it may be due to the synthesis of proper proportions of yellow and blue, of red, green, and blue, of purple and green, and a vast array of other combinations. A mixture of red and green lights may produce an exact match for a pure yellow. Thus it is seen that the mixture of lights will cause some difficulty. For example, the components of a musical chord may be picked out one by one by the trained ear, but if two or more colored lights are mixed they are merged completely and the resultant color is generally quite different from any of the components. In music of light, the components of color-chords must be kept separated, for if they are intermingled like those of musical chords they are indistinguishable. Therefore, the elements of harmony in mobile light must be introduced by giving the components different spatial positions.

The visual process is more sluggish than the auditory process; that is, lights must succeed each other less rapidly than musical notes if they are to be distinguished separately. The ear can follow the most rapid execution of musical passages, but there is a tendency for colors to blend if they follow one another rapidly. This critical frequency or rate at which successive colors blend decreases with the brightness of the components. If red and green are alternated at a rate exceeding the critical frequency, a sensation of yellow will result; that is, neither component will be distinguishable and a steady yellow or a yellow of flickering brightness will be seen. The hues blend at a lower frequency than the brightness components of colors; hence there may be a blend of color which still flickers in brightness. Many weird results may be obtained by varying the rate of succession of colors. If this rate is so low that the colors do not tend to merge, they are much enriched by successive contrast. It is known that juxtaposed colors generally enrich one another and this phenomenon is known as simultaneous contrast. Successive contrast causes a similar effect of heightened color.

An effect analogous to dynamic contrast in music may be obtained with mobile light by varying the intensity of the light or possibly the area. Melody may be simply obtained by mere succession of lights. Tone-quality has an analogy in the variation of the purity of color. For example, a given spectral hue may be converted into a large family of tints by the addition of various amounts of white light. Rhythm is as easily applied to light as to music, to poetry, to pattern, or to the dance, but in mobile lights its limitations already have been suggested. However, it is bound to play an important part in the art of mobile light because rhythmic experiences are much more agreeable than those which are non-rhythmic. Rhythm abounds everywhere and nothing so stirs mankind from the lowliest savage to the highly cultivated being as rhythmic sequences.

Many psychological effects of light have been recorded from experiment and observation and affective values of light have been established in various other byways. It is possible that the degree of pleasure experienced by most persons on viewing a color-harmony or the delightful color-melody of a sunlit opal may be less than that experienced on listening to the rendition of music. However, if this were true it would offer no discouragement, because absolute values play a small part in life. Two events when directly compared apparently may differ enormously in their ability to arouse emotions, but the human organism is so adaptive that each in its proper environment may powerfully affect the emotions. For example, those who have sported in aËrial antics in the heights of cloudland or have stormed the enemy's trench are still capable of enjoying a sunset or the call of a bird to its mate at dusk. The wonderful adaptability of the inner being is the salvation of art as well as of life.

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