PRIME: PHYSIOLOGY
Rainbow colours |
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In the 17th - century,
Sir Isaac Newton helped
us to understand, that light could be refracted
into its constituent colours when shining through
small droplets of water; each droplet, acting as
a tiny prism, dispersing light into the colours
of the rainbow.
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Newton's colours |
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Sir
Isaac Newton
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By 1802, Thomas Young
proposed that the enormous variety
of colours in the visual spectrum could be accounted
for, by only three types of particle, or cell, in
the retina, each corresponding to one of three colours
— red ,
blue ,
or yellow.
His idea (footnote 4.)
was taken up and modified in the mid-19th-century
by Hermann von Helmholtz,
who argued that each type of light-sensitive cell,
though sensitive to wavelengths over much of the
spectrum, was especially sensitive to one of three
types of wavelength — red ,
green ,
or blue.
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Thomas Young
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The
Young-Helmholtz tri-chromatic, or three colour theory,
had inspired much research. It had been particularly
useful in explaining inherited colour defects, such as
colour blindness, and the fact that a mixture of three
coloured lights could match any other coloured light.
However, it could not explain the phenomenon of colour
constancy, and said
little about what happens behind the retina in the brain.
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