Page 181 - Coincidences in the Bible and in Biblical Hebrew

COINCIDENCES IN THE BIBLE AND IN BIBLICAL HEBREW
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cones, S cones, or—most commonly, but misleadingly, blue cones. The other two
types of cones are closely related genetically, and in chemistry and response , and each
type is most responsive to light that we perceive as green or greenish. One of these
types comprises cones called long-wavelength cones, L-cones, or, misleadingly, red
cones. While L-cones are often referred to as red receptors, because the perception
of red depends on this receptor, microspectrophotometry has shown that its peak
sensitivity is in the yellow region of the spectrum, and it is most sensitive to light
we perceive as yellowish-green, with wavelengths around 564 nm. Another type of
cone is the middle-wavelength cone, also denoted the M-cone, or green cone. It is
most sensitive to light perceived as green, with wavelengths around 534 nm.
A particular frequency of light stimulates each of these receptor types to varying
degrees. Yellow light, for example, stimulates L-cones strongly and M-cones to
a moderate extent, but only stimulates S-cones weakly. Red light, on the other
hand, stimulates only L-cones, and violet light only S-cones. The visual system
combines the information from each type of receptor to give rise to perceptions of
different wavelengths of light. The sensitivity curves of the cones are roughly bell-
shaped, and overlap considerably. The incoming signal spectrum is thus reduced
by the eye to three values, sometimes called tristimulus values, representing the
intensity of the response of each of the cone types. Refer also to Figure 10.1.
The special structure of the human eye, and how it perceives colors, explains
why color TV and color printers can be based on the three so-called “primary
colors “—red, green, and blue (RGB ). These devices do not in any way reproduce
the true spectral color of the objects they show, but they are still capable of repre-
senting any color our eyes can see.
That part of the electromagnetic spectrum that is visible to the human eye
(namely, the visible light) have wavelength in the range between 380 to 740 nano-

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meters (1 nm = 10 meter).
Consider these examples for mixtures of red (R), green (G) and blue (B), and
the color they produce in the human eye:

R + G = yellow

G + B = cyan

R + B = magenta (purplish red)

100% R + 50% G + 0% B = orange

75% R + 75% G + 23% B = gray