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The Rudolf Steiner Archive

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Cosmology and Human Evolution
Color Theory
GA 91

The Theory of Color and Light V

8 August 1903, Berlin

The various effects of light rays on matter can be isolated. One can remove heat from luminosity by using an alum solution; and conversely, by using carbon disulfide, heat acts without the production of light. Certain rays of light separated from others can excite dormant faculties in a substance to activity or entirely annul them. For example, the rays that normally produce chemical effects, such as violet and ultraviolet ones, have the ability to make sulfur-calcium (a mixture of sulfur and the white metal calcium) luminous. However, if these rays are first allowed to pass through an aesculin solution, this effect will be cancelled, and the mixture will lose its ability of luminosity altogether. The ability to make sulfur-calcium luminous is possessed only by those types of rays that also produce chemical effects.

The red warmth rays have a slower vibration than the violet rays that produce chemical effects. The red ones have 400 trillion vibrations per second, the blue-violet ones 760 trillion, and even more so the ultraviolet ones; the light rays, bright in the middle, have an intermediate speed.

It is not that the vibration of the red warmth rays is slower, but rather the dark matter through which the bright rays shine and produce red makes the red rays more inert and passive. Thus the dark matter obscures the light and slows down the speed capability of the bright rays.

The violet rays cause the dark matter to take on a lighter coloring. That is, the dark matter itself undergoes a change, and therefore does not to disturb the vibrations of the light, but lets them pass. The dark matter changes the bright light rays by darkening them. On the contrary, the dark rays illuminate the dark matter and act on it, making it move and change.

When the light rays are caught by an object, darkness is created behind the illuminated object, and it will then cast its shadow on an opposite screen.

We can perceive an object's color due to the fact that, for example, a red flower vibrates the ether of light between itself and our eye 400 trillion times a second; that the light ether in our eye, set in the same vibrations, reaches the red cone in our retina; and through the optic nerve the image of the red flower which is reflected on the retina is telegraphed to the brain, whereby the reflection is then consciously perceived.

The astral can only perceive directly by empathizing with things. By being separated from things, man lost this ability of immediate perception; he places himself outside of things. He produces organs out of himself so that he may use them to produce images out of things; this enables him to perceive these images, and thereby perceive the things indirectly.

The light ether is now the medium, and the eye has developed as an organ of perception. The eye consists of the round eyeball, which is lined by the retina inside, which consists of rods and cones and is enclosed by an outer cornea. Facing externally is the open pupil and behind it the ciliary muscle, which holds a transparent lens. The ability to adjust causes the light aperture (the pupil) to widen in the dark and to shrink in the light so that not too much light enters, and to collect the light rays in a focal point; to let them fall into the "darkroom" of the retina, where the mirror image is produced and telegraphed to the brain by the nerve to which the eye is attached. Light and color are produced by vibrations in the ether. 400 trillion vibrations red, to 760 trillion and above in a second blue-violet.

The vibrations of air produce sound that are trillions of times slower than light waves.

The perception of air vibration as sound is between 16.5 and over 40000 vibrations per second. Below 16.5 and above 40000 vibrations are no longer perceived as sound.

Between 40 and 40000 vibrations per second musical tone is perceived.

For the measurement of the sound vibration of the air we make use of a rotating disc provided with holes—the siren. If the disk is rotated and vibrates under sixteen and a half times—that is, the air is driven through less than sixteen holes per second while rotating—we will hear only impact noise, not tone. The tone scale can be determined firmly by measuring the air vibrations in numbers. If we compare the prime C with the higher C, one C would relate to the other as 1 : 2, and within the octave we could determine the vibration ratios of the other notes.

Let's assume that the vibrations of the tone scale in the second were as follows:

The tone scale
Figure 1.

so we get the following relationship:

The prime to the octave = 1 : 2 = 1st prime
The prime to the second = 8 : 9 = 9/8 second
The prime to the third = 4 : 5 = 5/4 third
The prime to the fourth = 3 : 4 = 4/3 fourth
The prime to the fifth = 2 : 3 = 3/2 fifth
The prime to the sixth = 3 : 5 = 5/3 sixth
The prime to the seventh = 8 : 15 = 15/8 seventh
The prime to the prime = 2 octave

The shades of color behave within the color scale as the pitches behave within the tone scale; the ratio is the same, only the light ether vibrates trillions of times faster.

400 trillion vibrations red
450 trillion vibrations orange
500 trillion vibrations yellow
532 trillion vibrations green
600 trillion vibrations blue-green
665 trillion vibrations blue indigo
750 trillion vibrations indigo
760 trillion vibrations violet
700 trillion vibrations ultraviolet

An ultraviolet would be about the octave of prime = red. Our violet, at 760 trillion vibrations, corresponds in the tone scale to a tone slightly above the seventh.

There is a certain amount of time required for light to propagate through space. The speed of light is approximately 300,000 kilometers per second. This has been calculated both astronomically and terrestrially, and the results of the calculation have given the same result. The cosmic calculation has been made by Olaf Romer, based on the following observation: One has calculated the time, which the four moons need, in order to orbit around Jupiter, and waited with the telescope, until the two moons, which stepped into the shadow behind the Jupiter, appear again. This has produced the irregularity that the moons have sometimes been delayed—and up to 996 seconds longer than they were expected to be. The cause of the delay has been sought, and in the process the discovery of the laws of the propagation of light has been made.

The circumference of the ellipse that the Earth circumscribes around the Sun is 299 million kilometers. A much larger circumference is drawn by the ellipse of Jupiter around the Sun. It has now been observed that the moons always emerge from the shadow at exactly the right time, when the Earth is in a straight line between the Sun and Jupiter.

Now one waited for the time when the Earth arrived at the opposite point, crossed the whole width of its ellipse and puts the Sun between itself and Jupiter. Here the difference of 996 seconds has been observed; consequently the delay has been caused by the space which the earth has covered in the meantime. So the light needs 996 seconds to propagate through a space of 299 million kilometers. In one second it would need the 996th part of 299 million kilometers for it. 299,000,000 / 996 = 300,200. So roughly 300,000 kilometers per second.

The same calculation has been made by Fizeau with a gear. If one has a light behind oneself and a very distant mirror reflecting it back to the eye, and then brings a gear wheel between the eye and mirror and sets it in fast rotation by a crank, then one will see the light through the tooth gaps of the wheel until it has covered the distance back and forth; then the obstacle, the darkening occurs through the opaque gear-tooth. Now, if you measure the distance from the eye to the mirror twice and calculate the time, i.e. how long the wheel has to turn until the light gets from the gap to the tooth, you can also calculate how long it takes the light to propagate through space and return. This calculation agrees exactly with the astronomical one.

The speed of propagation is always the same, whether light or candlelight. Light is nothing other than ether vibrations which propagate in space.

With kerosene or a candle it is always the gas which burns; the liquid or the solid body is transformed by the heat ether into vapor or gas and then begins to shine.

If you make a solid or liquid body glow and deflect its rays with a prism through the opening of a darkroom, you get the continuous spectrum. If, instead of the glowing solid or liquid sphere, you pass a particular gas flame through a spectroscope, you get only a single-color line spectrum through the prism—a discontinuous spectrum—and exactly of the color of the gas in question.

Now if one tried to bring into the rays of the liquid body a glowing vapor, for example sodium vapor, there one found in the spectrum instead of yellow, a black line; the yellow was extinguished, absorbed. On this occasion, in 1859, Kirchhoff and Bunsen discovered the law of absorption: every glowing vapor extinguishes that kind of light which it itself produces, and allows all others to pass through it unimpeded.

Now that every substance has its own color which it emits as a gas and replaces it again by absorbing it from other rays of light, it is now possible to analyze every substance through the spectroscope and even discover unknown substances—for example, argon in the air.

This is also how one came to discover the dark lines found in the solar spectrum—the so-called Fraunhofer lines. One could thus analyze the material world of the Sun and state that it is of the same nature as ours. The glowing ball of fire is surrounded with an atmosphere produced by evaporation of the glowing masses of matter, and the rays of the liquid masses pass through the gas rays, which absorb their colors and give dark lines in the spectrum.

But these dark lines give a luminous band of colors as soon as a solar eclipse occurs and the moon covers the fiery ball of the Sun.

Through a spectroscope the state of evolution of the stars is also detected, and the character of the nebular patches, which may be doubtful through the inadequacy of the telescope, and which have often proved to be distant asterisms.

Only gaseous matter transmits any color and retains only its own color. Solids and liquids absorb all colors and reflect only the color which is their property, whether natural or artificially acquired.

What appears to us as color on a substance is only the reflection back of those rays of light which correspond to its color character, all others are absorbed.

Color is the property of a substance, the living expression of its acquired activity, its karma, and belongs to the karmic world, just as man is the product of his activity, his karma, for karma is life, is activity, is acquired.

Every substance or body is basically nothing but movement, it has its own mode of vibration and makes itself known only through the effects it exerts on other substances or suffers through them. Matter is always life and has a history; it changes through experiences, chooses and suffers. Any simple substance we perceive is in itself highly differentiated.

Light can be either primary—a self-luminous body—or polarized by reflection. In the former case, it has not yet lost its full vibratory capacity by contact with another body. If one puts two mirrors parallel to each other and brings them in contact with a candlelight, the light will be reflected twice in both mirrors. But if one places one mirror perpendicular to the other and brings it into relation with a candlelight, the reflection in the perpendicular one will be extinguished—it will not be present.

The cause is that the reflected light vibrates differently from the primary. It vibrates in all directions; now, as it is caught by a mirror image, this same light changes its mode of vibration, in that the mirror lets all other directions of vibration pass, absorbs, and lets only the parallel ones, which correspond to its mode of vibration, radiate back. This reflected light, which vibrates only in one direction, is reflected by the parallel mirror, but not by the perpendicular one. The first mirror is called the polarizer because it polarizes the light, and the perpendicular the analyzer because it shows the polarized light by extinguishing it. One can also use tourmaline tongs to investigate whether a luminous body emits its own light or only reflects light. Polarized light would be reflected only when the tourmaline is in a parallel position; when it is in a perpendicular position, there would be no reflected image; and when it is rotated obliquely, the light rays would partially vibrate with the tourmaline, and the different directions of the vibrations would form colored figures, similar to the Chladni-sound figures. In contrast, primary light would reflect at each position of the tourmaline tongs. In this way, planets and fixed stars can be recognized by their light.

If one brings a body between the two metal plates of the tongs, the darkened light will shine again, for the light vibrations are again regulated by the body's own movements.

If the rays of the Sun are caught unobstructed by a prism in a darkroom, a white disk with a darker perimeter will show up on the opposite wall, and this penumbra will contain the prismatic colors. The rays entering through the narrow aperture overlap and appear as colors at the boundary between light and dark; so, too, in mirror glass, colors are seen when the light is reflected.

Colors are the incarnation of light produced when the rays of light are stopped by matter and reflected back.