On False Color Images
by Randy Morris
The author is both a physicist and digital artist
A while ago I ended my neglect of astronomy and started putting together folders of the new images of our solar system and beyond, starting from the sun and moving out to Pluto, then to stellar images and extrasolar planets, nebula and dust clouds, our own milky way galactic center, the satellite galaxies, the more distant plethora of spiral, globular, exotic, and colliding galaxies, and finally the big bang background maps.
Along the way I studied my surprises, the fate of the probe into Jupiter for instance. I had the common picture of the outer gas giants, Jupiter, Saturn, Uranus, and Neptune as having frigid atmospheres giving way to strange, cold slushes that on earth would be liquid or gas, with maybe hot metal deep in their cores. In truth, after stars, they are the warmest places in the universe. The probe we sent into Jupiter, as expected, burned out in its hot dense hydrogen after sinking 150 kilometers (see Figure 1). Below that the atmosphere extends to hotter, denser hydrogen and helium, with nothing solid until the hydrogen becomes metallic (though at those temperatures and pressures our usual distinction between liquid and solid doesn’t mean much). The radius of Jupiter, at 70,000 km, is almost twelve times that of earth at 6000 km. At 10,000 km in depth, Jupiter is hotter than the surface of the sun, and near its center is close to 40,000 deg C with pressures of 50 million atmospheres.
Figure 1 Jupiter’s Interior and Temperature Profile
As hot and dense as this is, it is not enough to fuse hydrogen and turn Jupiter into a star. Jupiter would need to increase in mass by 300 hundred times for that to happen (the mass of the sun is about 1000 times that of Jupiter). Still, Jupiter radiates three times more heat than it absorbs from the sun. The heat is mostly residual energy from the gravitational compression that led to its formation. When we look at a picture taken in infrared, we can see the heat from the interior through breaks in the upper, cooler clouds, as shown at the right in Figure 2. Compare this with the common probe picture of light reflected from the sun at the left in the figure.
Figure 2. Jupiter in Visible and Infrared
This brings me to the main subject of this article. The infrared picture in Figure 2 is “false color”, since our eyes do not see in infrared. The picture could have been shown without loss of information as a “black and white” photo, since the infrared camera only measured intensity over a narrow spectral band at 5 micron wavelength (wavelengths of visible light go from .4 for blue to .7 for red). For effect, the picture is colored by mapping the intensity into white, yellow, red and black rather than black and white. This gives the impression of heat since this color scheme resembles what we see from a piece of hot steel in a forge. This impression reveals more about the nature of the inner Jupiter than the sunlit colors from the cloud tops.
The impression of heat, then, does not come from the colors of the image itself, but from our experience, from what we associate with those colors. It is an example of the old adage that we see with our minds, not just with our eyes. Although generally believed, I do not think most of us realize the extent of it. The distortions added through our neurological processing, forged through evolution to improve recognition, dwarf those we might have ethical concerns about. Look at the growing number of documented optical illusions. Or look at how large the full moon seems close to the horizon compared to when it has risen more. The moon illuminates the same sized patch of neurons in the retina in both cases.
Trying to capture an image with a camera as our eyes in truth would see it, is nonsensical in the most literal sense. The simple camera does not catch the same information as our eyes, for instance the parallax offsets that give our impression of 3D. In any case, photographic images must be “re-filtered” through our eyes. Moreover, as we all know, what comes out in a photo depends on a large number of peculiarities in the recording mechanism, whether digital or not.
Take for example the initial images from the first Mars lander. The first released photos were recalled because they showed a blue sky. The re-released photos showed a pink sky, more correct because it was the dusty season on Mars. Since then I have read a number of articles on how to properly correct the color to look like what we would see if we stood on Mars. It turns out not to be that simple, and some of the articles suggested more research was in order to be really sure, and even then we might not get it exactly right without modifying the cameras we put on future landers. Of course, even on earth the colors we observe from any given object and scene change with time of day, and our own eye adjustments to the ambient light. Getting all that exactly right with a camera here is no easier than on Mars.
The point I’m getting at is that when we do process a photo, or finish a painting, that most of us subjectively would judge as a realistic or convincing rendition of a natural condition, it is the result of many adjustments of the image that would take some time for us to analyze thoroughly. Many of these adjustments address our neurological processing of the image as it progresses from the retina into our cognitive mind. Some of these adjustments trigger associations with other images in our memory for effect. Moreover, the meaning we place on the entire image originates from associations in our memory, most beyond the purely visual.
The question then, is why this complicated process raises issues of ethics and aesthetics. Where must lines of accuracy be drawn that make one image ethical and aesthetically pleasing, and another a misleading or unaesthetic distortion? And remember, we are not talking about anything as clear cut as adding an extra tank to a front line journalist’s photo. To answer this I must digress into the history of formalism in modern art, so bear with me.
According to popular accounts, Greenberg invented formalism around 1940 to purify art by forsaking any form of symbolism or illusion. In this way art could be insulated from the corruptive commercial and political influence of popular culture (referred to as kitsch). Greenberg further restricted the true formalist path in modern art to that which he felt carried forward the spirit and rigor of cubism. Despite Greenberg’s own later recantation, and the current dismissal of Greenberg’s narrow interpretation, the “ethics” that sprung from the many varieties of the formalist dogma of purity, still carry influence in the way that art is created and viewed. In the following I will not adhere strictly to the Greenbergian interpretation of formalism, or address in detail the social and psychological motivations behind the theories, since that would lead too far afield. I will try to follow at a fundamental level, the thread of formalist ideas which underlie “ethical” concerns.
The foundation of formalist dogma in modern art rests on a notion of intrinsic beauty. Intrinsic beauty cannot be revealed merely by smearing paint on a canvas, or printing colored dots on paper, or by mixing phosphor intensities on a display screen. To see intrinsic beauty, according to one account I read, you must follow a process of disassociation. You must meditate on the “thing in itself” until it sheds its usual utilitarian connections and reveals the underlying qualities of its form. By this method you can readily see that a phone (the old rotary variety) remains mundane, while toilet bowls become sublime (as discovered by Duchamp).
Thus to get to inner beauty the quickest, objects as art must be presented as themselves without illusion. Hence if you must paint, the real value comes from the smears and stains, the texture of the canvas, for their own properties. The paint and canvas must induce sublimity on their own without specific reference or association to other external images or ideas, thus making art less vulnerable to human corruption and better able to connect directly to universal sources of shock and awe. Exploration of intrinsic beauty requires no further quotes from the broader spectrum of reality. Just like a mathematician, a modern artist should need no more than a pencil and paper.
However, if intrinsic beauty comes from a process of removing associations, what meaning is left? How do raw globs of paint, or more refined stains, or large areas of single hues, become sublime? Clearly the process of disassociation is not taken all the way to completion. The color and shape of paint blobs, or fields of color, carry more general association with emotion, movement, even the gestures inherent in the act of painting.
For example, take the arguments over the implied gesture in Pollock’s drips and splashes. Some critics thought it important that this impression reflected the way Pollock flung the paint on the canvas. It turned out that Pollock carefully dribbled it on, often with paint sticks, to produce the impression of motion. Sorry, no real flings in the actual act, though imitators probably did learn to do it correctly.
Let us define ethics here as a set of rules for conduct in the creation of art in accordance with aesthetic principles, for instance, the principles of formalism. What is usually meant then by ethics, or aesthetic correctness, in modern art, is rigid adherence to the formalist principle of using art objects for their inherent beauty, that is, by restricting manipulation of an art object to only the inherent properties of the object which have no specific association to other external objects. Ideally this should be done without illusion. However, I enjoy Pollock’s paintings because of their illusions of depth and motion and gesture, not because of the intrinsic beauty of the paint blobs. The extent to which art should accept illusion, and what should be called illusion, is still open to debate among the formalists and anti-formalists.
Rauschenberg is cited as the hero of anti-formalism. His use of photographic imagery is sometimes given as an example of explicit symbolism. Yet I find the use of “found” photographic imagery in his work ineffective as symbolism, though the photos do work as texture and non-symbolic imagery. Moreover, if you compare his work to formalist painters like Klein and Motherwell, it is hard to make much structural distinction. Take the works hung together at the Hirshhorn at the Smithsonian (see Figure 3). All of them use primarily horizontals and verticals within a two dimensional design with slight intonations of shallow depth. Rauschenberg includes more varied, incorporated shapes and objects, but in the same flattened format (more flattened in fact than much cubism), except for the small faded photos. Also, Rauschenberg’s incorporation of block print, is purely formal. It spells out no message (thank God), and is treated as a design element.
Figure 3 Comparison of Anti-Formalist and Formalist Paintings
Inevitably in modern art, the formalist notion of inherent beauty is applied to all imagery, especially photographic imagery. Many modern artists still treat photographs as things in themselves. In general this leads to very dull results, unless the artist violates the principle and finds ways to make the illusions inherent in the images work aesthetically. (Take for instance Rauschenberg’s “flying” diver photo in the upper right of “Dam” in Figure 3).
I believe it makes more sense for artists to unfetter themselves, go after the illusions, and make direct use of the referents on as many levels as possible. The pre-modern paintings that people crowd our galleries to see, are filled with illusions and referents intended to convey meaning. Unfortunately, the aesthetic techniques employed by pre-modern artists, especially those that use plastic (i.e. volumetric) figures as the major design element, are poorly understood by generations of artists who practice methods heavily influenced by formalism.
Perhaps if artists do break free from lingering formalistic restrictions, we wouldn’t hear the silly assertion that an artist becomes successful only after our culture first strips any antagonistic meaning from their work to make it socially palatable. If this idea referred to the censoring of film, such a thing might be plausible, but the assertion is made when the only action done to the work is hanging it in a gallery. The implication is that for proper understanding, a modern art work requires a polemic from the artist. Formalism aside, it is always much safer for artists to build their antagonistic messages directly into their works rather than relying on flyers at the gallery door.
Getting back to false color images. The now familiar pictures one sees from Hubble or other telescopes, of the diaphanous nebula or dust clouds, especially in the stellar nurseries, are almost all false color (see the astronomy picture of the day website). Many of the color mapping schemes have been codified. For instance, the Hubble Palette maps emissions from sulfur, hydrogen, and oxygen atoms into red, green, and blue hues. The responses from the three phosphors in the cones of our retinas are not nearly fine enough to distinguish the different patterns of spectral lines emitted from these elements (see Figure 4). That requires special astronomical instruments. The color schemes enable us to incorporate the results of spectographic analysis and see more information than the unaided eye.
Figure 4 Eye Phosphor Response Spectra versus Emission Lines for Oxygen and Sulfur
In a sense we have invented new eyes for ourselves. In the future we could devise neural processing to do this automatically from the output of our astronomical instruments and feed it directly into our cognitive mind for the same effect, or maybe more advanced effects. The goal of false color images is to convey more information, to enhance our awareness of the beauty of the natural world. Since the natural world is so vast compared to the small part we perceive directly, using all the associations and referents possible still only shows us a sliver or less. Our art should follow suit. We should try to open it to all that is possible. “Ethics” that would hinder this, is false ethics. We should practice false color, not false ethics.