Computer graphics has been in existence for more than 20 years. From the beginning, people experimented on ways to use the new medium—in addition to scientific, technical and commercial application—for artistic goals. Around 1965, Germans Frieder Nake and Georg Nees and the American, A. Michael Noll, strove for that goal; they were followed by individuals such as Kenneth Knowlton, the team of Charles Csuri and James Shaffer in America and the Japanese Computer-Technique Group. All of them were represented in the large exhibition Cybernetic Serendipity'' in 1968 in London.

In the following years, in addition to mathematicians and programmers, more and more professional artists adopted the methods of computer graphics. This became an international activity, but was little known to the general public. The situation changed a few years ago, not so much because of a breakthrough in the field of art, but as a result of the production of spectacular computer-produced special effects for science fiction films and advertising commercials.

As a technical method, computer graphics no more is involved with art than pencil and color. It becomes interesting only after it is applied to creative goals, and even then it needs the creative human being to achieve high quality, aesthetic results. In view of the short time that computer graphics tools have been at our disposal, each computer graphics work of art should be looked upon as an experiment to test the medium for its suitability as a means of artistic expression. We have here the unique case of an art in statu nascendi,'' the extraordinarily interesting initial state of an art which eludes all classical fields of observation, to be observed in its emergence. This is a special opportunity which, strangely enough, scarcely has been exploited up to now by relevant scientists.

One noteworthy observation in the evolution of computer art is its development from playful experiments to commercialization. Another is the formation of different styles and criteria of valuation, a phase not yet concluded so far. This article will concentrate on yet another aspect of this discipline—the interaction between technical instrumenta-tion and artistic expression.

In the fifties, the mechanical plotter'' was the only drawing apparatus in use. According to a program, the plotter controlled the movement of ink, pen and pencil, over flat paper or paper stretched over a roll. This method limited artistic experiments with computer graphics to line drawings, initial production of block diagrams, wiring diagrams, maps, etc.

Software, as well as hardware, affected these artistic experiments in design. The first programming languages were particularly well-suited to describe mathematical and logical associations. The first computer artists used these existing routines, so it is not surprising that many of the things produced then originated from the rich store of forms in technique and science.

From the view of artistic trends, these works are formally related to constructivism, especially concerning the precision of presentation and the limitation to simple form elements, which were then still necessary. While representatives of classical constructivism had to make do with a ruler and compass, thus being limited to straight lines and circles, it is easy for the computer user to insert precise and complicated curves. This is possible either by the process of interpolation or by the program evaluating mathematical formulas and transforming the resulting numbers into graphic presentation.

Another expansion of form and style, accessible with programming languages, concerns the transfer from order to chaos. With the help of a random number generator, one can get essentially orderless rows of numbers which can be used as reference numbers for graphics presentations. The use of the chance effect, common in the early days of computer graphics, also found expression in manually produced constructivist works, such as those by Herman de Vries. Some constructivists, like Peter Struycken, Zdenek Sykora and Gerhard von Graevenitz, used the computer to realize their picture ideas.

Different effects were achieved by using methods of image processing, that is, the graphic processing of data. Originally this technology was used by scientists to enhance pictures obtained photographically. With digital electronics, a considerable widening of this field of activity was possible, such as being able to correct distortions of pictures or eliminate noise.'' Distinguished from computer graphics, image processing works with pictures of real objects and scenes, which are thus open to artistic treatment. Again, already written computer programs are available to artists, who use them to distort pictures rather than to improve them. This can lead to attractive graphic effects.

The beginnings of image processing go back to the time of printers and plotters, but the real impetus is connected with television. This technical innovation, with the appearance of the picture tube as a presentation tool for computer graphics, initiates a significant change. With color screen limits of more than one hundred million hues, the number of available colors is greater than the number of colors the human eye can distinguish.

Contrary to the plotter presentations, the construction of which often took more than an hour, a picture is now created within fractions of a second. This permits interactive work—there is essentially no waiting time—and the producer immediately can see the results of his graphics applications and improve upon them until the effects are optimal. This also eases the capture of movements over time. With bigger systems, sequences of 30 pictures per second can be created in real time. For the first time, the visual artist has a means to create graphics sequences freely.

Whereas the limited possibilities of the plotter favored a trend toward mathematical constructive presentations, the monitor picture gives the artist relative freedom. Today, computer graphics is not bound to a certain style but depends on the views of the artist. If he wants to use the so-called paint systems, which allow for simulation of hand-drawn objects, he achieves a flexibility hardly imagined before: he can mix and change paints at will, turn parts of the picture, move, manipulate or erase; he can withdraw objects and enlarge details which are then zoomed back into the picture, etc. Pictures produced in this way do not differ significantly from those achieved with conventional methods.

Some artists have discovered the wider possibilities in style and expression that can be realized with computer graphics, unknown in classical painting. Mathematical formulas, used since the early days of computer graphics, have been applied more rigorously to current work. A significant difference results. With conservative working methods you go point-by-point, meaning that in a picture, the exact spot you touch is changed. Computer graphics also permits changing the picture in its entirety.

In this field of mathematical techniques belong transformations. When applied to images, these transforma-tions yield manifold changes. In simple cases, a transforma-tion can cause an exchange of colors, a physical structure or the accentuation of contours. With more complicated trans-formations, new picture structures can emerge that do not resemble the original. A picture can be formed by applying different transformations, or by modifying form and color manually. A mathematical law says that, in this way, any picture may emerge. Both methods are also complementary.

An even more remarkable computer technique available to artists is the ability to create three-dimensional perspective presentations. Just as line-drawings of plans and maps influenced computer art in the beginning, today's computer-aided design applications are influencing 3-D art. In place of physical models of machine parts or buildings, there are pictures that can be observed from all sides; a change of the viewing angle can be achieved from the control panel. A 3-D representation of the object is stored in the computer. Software computes the desired views and displays them on the screen.

With the help of special programs, 3-D objects and scenes can be made to look real. Once the user specifies the number and locations of light sources, software removes hidden lines and hidden surfaces, and adds shadowing and highlights according to the laws of optics. Last, computer graphics programmers developed algorithms for realistic generation of mountains, clouds, water, living beings, etc. Some of the effects are so astonishing that they are taken for works of art in themselves. At previous exhibitions of the annual SIGGRAPH conference, artistic works were displayed alongside images showcasing technical achieve-ments and creative programming.

And yet, it would be a mistake to deny this medium's artistic potential. The development of programs has proven to be the necessary basis without which no artistic achievement in this field is possible. It is the realm of photorealism, the style dominant in art circles some time ago, which demanded the rendering of scenes from everyday life as realistically as a photograph. Although the results of this style are not distinguishable from painted works, there still is a considerable difference. In the application of 3-D routines, the artist is concerned with more than the surface of things—quite another approach from the reproduction of perspective projection. It is evident that we have here a real expansion in presentation, as the objects presented in this way can be observed from all sides, as well as through time. If we deal with moving things, e.g. an animal, then the dialogue between the artist and his object goes further still. He may think about the interplay of skeleton and muscles, the degrees of freedom of movement, and finally, create a film of the creature in motion. Here again, the effect alone is not sufficient to make the presentation into a work of art, but the availability of the method presents an enormous challenge to the artist who now has means of expression hitherto unavailable to him.

The experiences with the first picture sequences created this way show that realism is relatively uninteresting. As has been confirmed in other fields of art, an exact copy of reality is not what counts. An entirely new dimension opens for the artist when he moves from realism to surrealism, just as with image processing, which serves not only to improve'' pictures, but also to make them abstract and interesting. For the first time, he has the possibility of building scenes of his fantasy in three-dimensional form, to give shape to worlds that do not exist in reality and, perhaps, cannot exist.

The hardware and software needed to create real and surreal pictures are still extremely expensive and limited in number. For the artist who wants to use these systems, it is difficult to find and gain access. But at those rare happenings where highly developed technique and artistic talent come together, there originate examples of surreal forms with the potential to initiate a new epoch.

Among the few pioneers of this trend are David Em, an American, and Yoichiro Kawaguchi from Japan. Today, their art might still appear exclusive, just because the method applied is at the disposal of only a few. But we can see already that hardware and software for computer graphics presentations are developing and spreading quickly. What is still a pioneer achievement may, in 10 or 20 years, belong to the ordinary fields of artistic activity.

J. S. Bach's last unfinished work, The Art of the Fugue, is a magnificent network of simple theme and variations that are interwoven, transposed, inverted and retrogressed. Some believe that Bach's counterpoint, which consists of a complementarity of voice-parts, exhibits an affinity with algorithmic computer-program instructions and procedures.* I agree, and I believe that a video counterpoint offers a special complementarity between its own musical and its visual voice-parts.

Will computers allow a new art of TV as pure and popular as Bach's music? With suitable talent in place, I believe so. Formal principles can be composed into algorithmic software. But more to the point of this essay, composers can invent algorithms with which to process both musical and graphic rules and aesthetics. In short, there are new pattern potentials for music-with-art.

Color and music have more potential for fusion than imaginative composers, poets and artists believed possible. From Aristotle to Scriabin and Wassily Kandinsky, visionaries repeatedly invoked the mind's poetic image of intertwining color with music. Inadvertently, this dream devolved into a kind of collective vision which, after these many centuries, is near to actual realization, hence the spread of TV's present stylish'' pop MTV.

Yet, MTV needs substantiality to realize that ancient collective vision. Computers can contribute substance by expanding music's art of time. The computer's clock allows compositions in time which can be as sensitive as real-time performance. In fact, we've acquired high-resolution numerical control of time itself. Solid-state instant replay, expanded memory plus greater speed and bandwidth sharpen the creative potentials. Graphic geometry, infused with the vitality of color and motion, gains the full emotive power of music. Systems architecture of this decade has produced music and graphic generating capabilities all in one computer instrument. This has become the artist's first universal machine.

Founded on a universal-machine concept, my own study of color-in-motion began in 1965 as a search for aesthetic roots while developing software and interim instrumentation. This exploration of computational digital harmony'' gradually substantiated the point of my reasoning. Differential functions within various geometric algorithms generated order-disorder graphics (harmony). Mathematical expressions, plotted frame for frame on file or video, produced subtle clues that helped me to clarify this hypothesis with each new film.

Eventually, it came to my deeper understanding that a differential arithmetic of resonance actually embodies the architecture of music. This arithmetic productively complements a graphic differential geometry. Visual patterns, derived from simple periodic geometry, produce order/disorder resonances in actions which complement the consonances and the dissonances, the tensional dynamics and the universal emotive power of musical rhythm and harmony. These were summary conclusions I was able to draw from my study and films [1,2].

Thus I was able to accept as an operable fact that the basic, quantifiable units of construction for this computer art are: (a) the pixel points of color and (b) the pure audio sine wave. These two root components enable one to compose periodic and polyphonic artworks in graphics and audio, as if these elements were building blocks with which to construct a generative graphics and a new musical scale. These elements provided a complementarity between sight and sound, and they suggested the foundation for an aural-visual art.

We may compare the implications of two terms often associated with computer music: synthesis and genesis. My studies suggested that composing music by computer should stress algorithmic or generative processes of genesis. Basic elements, pixel and sine wave, can be generated from ground up,'' so to speak, into visual patterns as well as melodic patterns of specific timbres, all by algorithmic rules invented by the composer. This proved to be a departure from most improvisatorial composing procedures of synthesis, for example, often accomplished on real-time keyboard synthesizers.

It seems to me that much creative effort is misguided because of an insensitivity to this major issue of synthesis vs. genesis. The arbitrary wave-form envelopes of all tone synthesizers, keyboard improvisation, and even of present day Expert Systems applications to music synthesis, create a world which is just that: synthetic.

Our experience will finally teach us that a computer instrument offers a genuine potential for audio-visual art that is not synthetic and not a synthesis for an imitation of the creations associated with either the gallery or concert hall. Computer art belongs elsewhere in a different cultural community. Television needs music-television just as much as MTV needs good computer graphics and computer music. Here, we might employ Expert Systems more wisely than merely to imitate a grand piano.

The very concept of genesis prompted my ideas about pattern potentials for music with art. Filmmaking demonstrated to me that all 12-tone methods and traditions, requiring fixed tunings, notation and instruments, could be replaced by acoustic algorithms in association with graphic algorithms. Here was new methodology for digital harmony. I had uncovered the harmonic basis for composing music in interactive interplay with color design and action. Located outside instrumental/vocal traditions yet retaining a valid harmonic foundation, digital harmony may (or may not) be a new and different approach for an evolving species of composer/artist.

My guess is: a powerful appeal lies within the natural interlace and active coordination of eye to ear, and ear to eye, at the integrated level of digital aural-visual harmony. But who's to foresee the expressive power of these relationships until they're brought to life in many, many successful works of art? Some have doubts about the power of harmonic pattern, but we must not forget what is already well known. Examine the 20 or so fugues in Bach's last work to see how harmonic pattern, constructed from a mere 12 tones, probes the depths of human feeling.

A computer's expanded, heterosensuous opportunities for art were never before understood; without digital systems, they weren't even subject to exploration. Now, overnight, the methodology is at hand. Long ago the refinement of the Baroque family of musical instruments opened floodgates, permitting certain music that has been popular now for some 300 years. Just so, we may expect that the perfection of realtime audio-graphic computer instrumentation (including a feasible interface with TV) promises an avalanche of popular work among those pattern potentials for music-with-art.

Art's relation to its instrumentation is the ongoing subject of interest; my own experience shall provide this concluding anecdote:

It was with a homemade device, a simple sinusoidal pendulum array and optical-printer instrument, that my brother and I composed our first international success in the rarified avant-garde of 40's-style MTV. This early triumph implanted in our minds an urgent lifelong drive to gain access to a perfected facility that would provide music and graphic capabilities unified within one instrument. This was at least 30 years before computer technology would make that instrument a reality.

Out of the strength of our convictions regarding this instrument, we conceived an indelible dream of auralvisuality within a brand new artform. Thereafter, reflectively, for years I envied Domenico Scarlatti and Antonio Solar, who, by royal or Papal largesse, were provided the instrument and the patronage with which to compose hundreds of simple essays exploring a keyboard artform that was mostly of their own invention. Would that brother James and I had had such a gift'' of instrumentation. And yet, it's here!

For 20 plus years, I have participated in computer art'' as a developer/experimenter/inventor of languages/ interfaces/techniques, as a collaborator/teacher/writer and as a computer artist.'' As a result of all this, I finally feel like an established practitioner in an enterprise that doesn't (at least not yet) exist. Here's why:

Conclusion: We are not yet beyond the gee-whiz stage of cuteness, of stunts and of novelty for its own sake. In order for the artist to get into serious art, he/she must have a more nearly complete command of the tools, including the understanding and ability to build, redefine and/or augment them. Similarly, because of the awkwardness of interfaces, the artist should have control over the mapping of human actions into directives to the underlying operations. These are not new ideas—in a computer environment such features and behavior are understood implicitly and expected. How to do the same for artists is not quite so clear because artists have somewhat different temperaments, methods and purposes.

At this point, it does not make much sense to me to be trying to produce better computer art. The more appropriate challenge is to create better environments for the development of art-making tools.

Computer art is unfolding on the basis of scientific and engineering achievements of pioneering personalities, whose vision suggested that it should be possible to wrest something other than calculation speed and numeric precision from those crude and clumsy computers; something that could be turned into meaningful images. They set out to build dedicated machines to interpret an intuitive stroke with a pen or a snapshot taken through the lens of a camera. They designed displays that show more colors and change images faster than the human eye can distinguish. They devised software to generate pictures that appear just like photographs of reality. All of this has been accomplished within the short timespan of two or three decades. The history of computer graphics reads like a tremendous technical success story.

Conceptually, the way had been paved by Alan Turing's contributions even before the first computer had actually been built. Turing had reasoned about the ability of a computer to act intelligently. He realized that all a machine needs to perform are read and write operations on sequences of symbols. These symbols can represent anything, obviously numbers, but similarly, letters, or as we commonly know today, colors, geometries and other visual features. Symbols can be arranged in larger complexes to stand as tokens for aspects of reality or fictional models. The computer serves as a dynamic symbol processor by altering any given symbol in any order. Turing compared the machine's functions to humans' use of language. He argued that both activities share the processing of symbols—the only mental phenomenon from which results are directly observable. Thus, he concluded, the computer can exhibit the same intelligence we attribute to human beings. In principle, a general purpose computing machine was conceived. In one of its incarnations, it can act as a universal image generator [1].

Turing's inferences remain hotly disputed, since they bluntly grant intellectual powers, widely believed to be the exclusive possession of humans, to machines. Opponents argue that even if a machine could conduct limited rational reasoning it could never exhibit genuine creativity. They define creativity as the production of something original, something without precedent. Creativity implies the capacity to break those rules voluntarily that are slavishly executed by logical deduction, and consequently is considered integral to artistic pursuits. Modern art, in general, disregards existing value systems and continually posits completely novel conditions. Academic codifications of art have been undermined and extended by an ongoing succession of new art movements, manifestos and methods.

By severing its ties to the social context of religious and political rituals, art became the essence of truly personal experience that is condensed into special forms of individual expression. Because each piece of art is unique as a symbolic manifestation of the spiritual potency and handicraft skills of its creator, it is considered to be precious both in immaterial and marketable terms. This foundation of art was never questioned until Marcel Duchamp invented his readymades,'' which were utilitarian, prefabricated mass products that he chose to elevate into the domain of art, simply by declaring them to be art. Duchamp's surprising gesture of placing an ordinary, industrially manufactured urinal as a piece of art into the sacred halls of a museum shocked even the liberal consensus of the avant garde. This readymade'' had not been ennobled by the creative hand and spirit of the artist, and to make matters worse, it directly confronted the public with issues that were suppressed because they were considered obscene. A scandal was inevitable [2].

With with one innovative stroke Duchamp shattered the endless cycle of discussions about validity and virtue of this or that ism'' and radically probed into the very foundation of art. His ironic questions remain unresolved but continue to influence the contemporary understanding of art. Duchamp's readymade'' was the result of his sharp reasoning about the impact of industrialization of art. It was fashioned to ridicule the closed circuits of a narrow-minded art world. The readymade,'' with a Godelian jump-out-of-the-loop,'' discarded all prevalent aesthetic criteria for judging art [3]. It seems to me that our time is ripe for an equally strong and convincing statement that reflects on the dramatic changes inflicted by the computerization of factory, office, home, and of course, art. In analogy, such an artifact would take the very subject it covers into account and proudly proclaim itself machinemade.''

The outstanding and farsighted work of both Turing and Duchamp delineates the intersection of contemporary art and computer science. At times like these when new territories are being staked out, proven methods and yesterday's guidelines are bound to fail. Not only practicing artists are thrown back upon their personal judgment, but critics and audiences alike should seize the opportunity to scrutinize closely and discuss frankly the repercussions and extensions that computer technology is bringing to the arts.

The majority of artists use computers today to further cultivate their expressive vocabulary and to take advantage of the digital dynamics within the production process. In essence, they are either replacing traditional tools with sophisticated computer simulations or integrating computer imaging techniques by applying them alongside conventional methods. In the latter case, multi-media pieces are often collaged out of different image sources and materials. This approach helps to turn the highly malleable but intangible computer image into a durable work of art. Other artists follow routes that experiment more directly with the procedural character of imaging technology. They address topics such as change, chance and chaos, and visualize them in unusual formats such as combinatorial clusters of a complete picture space or multiple exposures of a gradual evolution.

Computer art provides exciting visual thought experiments,'' that would not be possible in other domains of human endeavor. A far-out example is the depiction of the internal memory of a computer. Patterns of behavior and organic growth processes are modeled in challenging and formidable attempts. Even Turing's far-reaching philosophical suggestions are being implemented in automatic drawing systems that simulate visual cognition. Computer environments represent the changing states of mind of an artificial time entity.'' Finally, Duchamp's dictum, It's the onlooker who has the last word,'' gains fresh meaning vis-a-vis the participatory potential of interactive computer installations that invite the audience to realize a very personal version of one particular piece of computer art.

In my own view, good computer art, like any good art, goes far beyond the thin skin of its physical surface. At its best it is smart art that can stimulate via visual symbols a rich variety of retinal as well as mental activities. These symbolic artifacts vividly trigger our perception and lead successively to deeper levels of cognition. Symbols are like shadows cast by the internal state of an organism, shadows that can be registered meaningfully by the counterpart in a dialogue. How are we to tell whether the originating organism is a human being or a machine? What matters in the end is that only through the eye of the beholder is an image activated and able to serve as the evocative agent that touches mind, heart and soul.

In the early twentieth century, modern artists, notably suprematists, cubo-futurists and constructivists, rejected scientific perspective and descriptive art [1]. Although this dismissal of the world of appearances in art was never accepted by the general public, modernism evolved from that rejection.

Computer art in the 1980s is, in turn, a rejection of modernism. The interactivity of computer art is tied to the revolutionary art of the early twentieth century; computer art in general, however, uses the dynamic dimensions of space rejected at that time.

Computer artists are replacing modern art concepts with new aesthetic qualities which include not just three but four dimensions, the fourth dimension being that of time. The aesthetic experience associated with interactive computer art is one of the most noteworthy discoveries of the masses.'' Computer generated images were embraced by the general public in electronic games early in the 1970s and now through the use of home computers. When amateur artists are drawn to the computer to make images, I call the production of their creative efforts, volksart.'' I differentiate between the term folk art,'' which commonly refers to primitive art, unassociated with industrialized technology, and volksart, which is the production of artwork by computer artists without formal training in aesthetics.

Probably because computer art intrigues the masses, it is slow to be recognized by the art world.'' One hears the comment that computer-aided art has no intrinsic worth, no discernable aesthetic qualities and is acritical [2]. Aesthetics is usually defined as the study of beauty. Contemporary usage of the term aesthetics implies a study of the design elements that make up any artistic endeavor, in this case, computer art.

The design elements that contribute to the aesthetics of computer art have developed as computer technology expanded and responded to visual needs. There are eight readily recognizable design elements that relate to how computers function to produce images that make up the computer aesthetic [3]. They are

Artists use the computer as a tool, designing works of art which they then execute in other forms, for example, plotter drawings and paintings.

Artists use the complete computer system as a medium in order to paint in light. The translucent quality of colored light as produced on the monitor is unmatched by any other artform.

Artists use the computer as subject for their visual research. Since art represents the era in which it was produced, some artists provide us with a view of the complexities of the Information Age and the impact of computers on our society.

The history of computers in art parallels the history of Western contemporary art. In the sixties, computer artists produced hard edge and op-art. In the seventies, artists attempted to engage the audience in participation; this has its counterpart in the development of interactive animation. In the eighties, artists returned to figurative imagery. It is the return to the descriptive that draws people to computer art. Artists and the masses have chosen to use the computer to create artworks in order to express our age, the Information Age.