7/29/2019 A Disc to Produce Subjective Colors.-english-Gustav Theodor Fechner.

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A disc to produce subjective colors.

of GT Fechner.

It is well enough known that one can produce through a rotation with colors painted

in an appropriate manner slice of white or gray. Strange as it seems to me that we do

not yet perceived a phenomenon which is in a sense the opposite of the

previous. Turning a rapidly covered with an alternation of white and black disc so

arise colors. I made this observation first chance. I had to create a disc by turning

various shades of gray, a cardboard disk par of 18 inch dia. can produce, which in 18

was divided equally wide concentric circular rings.The innermost was black, the next

contained 20 degrees, 30 degrees below the white surface, & c, so that thus the

outermost 18TE was all white. Plate III Figure 7 illustrates this arrangement as it

would be for only 7 circular rings. The outline of the black figure is, apart from the

corners (with division into an infinite number of circular rings), of an Archimedean

spiral. Now when this disc was shot, I was surprised, rather than shades of puregray's, but all sorts from the center to the circumference, so as the nature of the

rotation speed perceive changing colors not to my eye, not of strong intensity, but

were without animation. I have shown this phenomenon many people, and found that

it is perceived by them with very uneven clarity, which may not be conspicuous in its

consideration of subjective origin. Some called brilliant colors. Others could scarcely

see anything of it, but I think they are quite escaped no one. Goethe would have

found this disc may be very convenient for his theory by seeing colors appear here, in

fact, when in motion black (of course only to say so) pushes over white, or vice

versa. However, is the reason for the appearance indisputably the following: Put thedisc moving in the direction of the arrow, as occurs for the assumed to be immobile

eye with a black in place of the white, which was previously seen for a moment

there. The impression of the so equally saw light now does not disappear immediately

in mind, and although he does not for all color rays, which make up the white light,

just quickly, as evidenced by other facts (namely the color-fading in the closed eye

after being viewed bright images) can demonstrate enough, that I'll come back in a

continuation of my studies on subjective colors. The colors go after each other in the

eye now more or less, until upon continued rotation of the edge b in the place

ofa new white light comes and carries with it. But just as the impression of differentcolors different rays quickly disappears, he seems on the other hand also upon the

occurrence of light after dark to assert again with different speed, so this creates a

new reason to color phenomena. Depending on the disposition of the eye, the

distances between the edge ofa and b, which is different in the different annuli, and

the speed of rotation of a greater or lesser proportion of colors must now of course

already be extinct in the eye until new light on the eye encounters and new entrants to

the phenomenon of color is composed partially extinct, and this caused the variability

of the phenomenon, which can be brought difficult indeed to fixed rules.

However, I have tried to do this by watching how, then increasingly faster rotationdevelop and change the colors at first slowly, however, have other of the , what I

perceived this, can not perceive clearly what perhaps preferably on the increased

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sensitivity of my eye for subjective colors based.

In the precarious values that would have the subjective Single-perception, I will

pass over, and merely mention the following fact, I perceive themselves with the

greatest determination and the several others have noticed at least vaguely. If the disc

is turned so slowly that the individual prongs of figure can still be somewhat

distinguished, I see these teeth already lined colored, with vorwaltendem Green whenthe rotation occurs in the direction of the arrow, with vorwaltendem russet, when they

takes place in the opposite direction.

Prof. Mobius noticed when I showed him this experiment, another special

circumstance to which I had become myself not paying attention, but which is

striking and is perceived by everyone in the same way. If the slow rotation occurs in

the direction of the arrow, so the black character seems to expand, whereas if it is

done in the opposite direction to contract.Especially this contraction, this Einkriechen

the figure is very striking, but also the expansion in the first case unmistakable.

If one uses instead of a black figure on a white ground to a similar white on a black

ground, so to show similar, though modified in the brightness of color

phenomena. For moderate rotation speed, however, show the prongs lined rotgelb me

here, if the rotation occurs in the direction of the arrow, blue green with opposite

rotation. The apparent reduction or enlargement of the figure but occurs in the same

direction as the rotation earlier.

If you place a single white figure of the spiral slice on a black disk or vice versa

attached and put the whole thing in rapid rotation, so do not show up as expected, the

colors less.Using a white semi-circle on a black disc itself to me at a moderatelybroad daylight the phenomenon this way: at a moderate rotation speed, the wheel

turns yellow, then with increasing speed gradually yellow-green, green, beautiful

light blue. Through this, the disk about pulling inks general but flickers through a

colorful marbling, which during the yellow phase of the phenomenon mainly of blue

veins or fibers that pass through it by the yellow, is at more rapid rotation but changes

gradually. If the speed is increased to reached bright blue phase even more, no

uniform ink can be perceived, but the whole disk covered now with a wallpaper-like

pattern of contiguous multi-colored mesh or cells, with here and there stray larger

spots.This multi-colored cellular pattern is most consistent with this whole class ofphenomena. Namely, it was performed at a sufficiently rapid rotation of the disk by

different persons of different brightness of lighting, and also for sectors of angles

other than 180 , so is also the various annuli of the first-described wafer. Mind As to

the succession of the general color inks with increasing rotation speed, so I have not

even yet it clearly in direct sunlight, or even in daylight dawning in the specified

previously been able to perceive nature. I felt very strange when using the white

semi-circle under sun light falling directly the appearance of irregularly scattered

points, which radiated from the finest gold luster when the disc was rotated at a

constant speed.

If after publication of the cellular pattern colors, the speed is still further increased

beyond a certain limit, so does the clarity of the same speed increases

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again. Indisputably one would get the same clean gray with sufficient growth. In fact,

although I have with my command rotary engine to drive the speed in any of the

cases where a single alternation between White and Black took place in the whole

circumference to the point been able that a colorless pure gray would be published;

very easy but with several alternations, easy to expect what a difference even after the

cause of the phenomenon. Applying z, as a disc, which in divided 12 alternating white and black sectors, the

cell color pattern already appears at a very low rotation speed, where to see nothing at

all of them when using the white semi-circle, and it increases the speed a little more,

so it reflows patterns in the purest, most uniform gray.

It would be interesting to investigate, in which rotation speeds, or what number of

alternations between white and black (when the velocity is constant) for different

gray eyes that occurs by itself from this kind of a subjective measure of certain

peculiarities of the same could be found. I can not help but believe that the

appearance of wallpaper-like pattern, as it can have no reason in the object, based on

a variety of different points of the retina in rapid alienation and inclusion of different

colors namely sensations.

As a practical result would emerge from the foregoing that the Talbot (in this Ann.

Vol XXXV p 465) specified disk to generate different shades of gray 1) , essentially

the same as that which I have described first (with the spiral figure), its purpose does

not correspond very well. One has to get with moderate rotation speeds colorless

gray-applying to the quantities of white and black in multiple distribute alternations

in circles.1) It is very striking to me that Talbot has seen nothing of the same color in

many other particulars. At least there is nothing mentioned about it.