PURPLEXITY
©2003
David Kidd
Jimi Hendrix saw a "purple haze" in 1967, but Isaac Newton saw "indigo, violet" in 1665. What
shall we say in today? For three centuries all school children
had Newton's formula "the colors of the rainbow are red,
orange, yellow, green, blue, indigo, violet" drummed into
them. But since children can't ever find any indigo paint what did
Newton mean by indigo? And another thing: all modern color wheels
have six divisions, not seven, so why did Newton led us astray
with seven colors?
The answer is that indigo is a dark
warm blue that video technology calls blue, and what Newton
called blue is what printers now call cyan. By magenta they mean what Newton
called red, and what video technology calls red Newton would consider almost orange. See my COLOR WHEEL web page where I explain how the
meaning of the color names has changed in the RGB and CMYK systems,
and where I propose a new set of colors of the rainbow to teach
our children.
GOETHE'S FEAST
In fact Newton's spectrum of seven spurred Goethe to write a
book in retaliation:"Farbenlehre" in 1810. Goethe's
"theory of color" describes simple experiments that
prove there are only three primary colors, and that they are
equally spaced by three secondaries, making six. The one he drops
is indigo. Goethe's dramatic writing was as much stimulated by
Newton's Seven as it was by the legend of Faust. Goethe
said "no aristocratic presumption has ever looked down on
those who were not of its order, with such intolerable arrogance
as that betrayed by the Newtonian school...looking down with
a supercilious air on the ancient and less modern inquirers"
(preface xlv).
Sir John Leslie suggested that "when Newton ... ventured
to assign the famous number seven he was apparently influenced
by some lurking disposition towards mysticism .... betrayed by
a passion for analogy, when he imagined that the primary colors
are distributed over the spectrum after the proportions of the
diatonic scale of music, since those intermediate spaces have
really no precise or defined limits" (59). However I believe that
Newton's Seven was more inspired by the writings of Jacob Böhme for his visionary books also inspired in Newton
the discovery of gravity (Roob 253). Böhme had a mystical experience in 1600 stimulated by Genesis 1:5-2:3
and 7:1-8:12 where God creates and recreates the world in seven
day periods. And because Böhme wrote
that "light was born from seven source spirits" Newton
wanted to make his discriminations fit that number.
In my opinion if Newton had studied the origin of the number
seven more deeply he could have got it right at the beginning
As you can
read there, Judao-Christian tellers of religious allegories indiscriminately
apply the time unit of seven to any quantity. Did Böhme
and Newton misapply it to light? Oddly there is another connection
between the number seven and the spectrum through the origin
of words. Our word week is akin to the Latin word vicis that means alternation, and that is akin to the Greek word iris that means
rainbow. This coincidence may be no accident, as tellers of the
Deluge story traditionally indulge in word-play.
SIX AND ONE
However Newton and Böhme neglected a church doctrine that
the seven days of the scripture are made of six similar work
days and then a special one that is quite different and set apart:
a holy day. The week is not just a chain of seven equal and identical
periods because one is described as both the origin and the total
of the other six: "the reason for them" the church
says. As Newton persisted in wanting his spectrum to have seven
colors, his science could have fitted his theology better if
he'd described it as six colors with the seventh one as their
origin. By logical priority white is the first and total light,
and if we apply the same rule to pigments the first and total
pigment would be black. In either case when you look at the total
you will see no colors in it because when diametric opposites
are united they appear to neutralize each other, for example
magenta and green make a gray.
However opposite colors concur
in that they are both visible. Both origin and totality must
contain all antinomic affirmations. In the linear spectrum the
quality of visibility defines both the beginning and the end
of the spectrum line. However the origin is not the same as the
first because an origin is prior, and a total follows the last.
That is: visibility is not a color; in the same way that a week
is not Sunday. However one color could symbolize visibility in
the same analogous way that Sunday represents the week.
In making the spectrum line into a color wheel there must
be a location in the circle where the two ends of the line join:
it falls between violet and red, and that color is called purple.
Could it be that the One joins the split ends so that purple
is made of the two colors at once? A sketch I drew surprised
me by looking like the Greek letter Alpha. I soon found out that
Omega also makes a good design.

The color circle is more like a flask than a circle because it
has an opening at the top. Could purple symbolize the origin
and total of colors if it is embraces more than one color?

MODERN SPECTRUM USAGE
Lets examine the color purple and its current usage. Fresnel
(1788-1827) did experiments established that light can be described
as waves of different lengths: this is his solar spectrum with
the wavelength in nanometers:
700 magenta620 red590 yellow560 green485 cyan465 blue425 violet400
Lets define what were talking about: it's the colors that lie
between blue and red on a color wheel. More precisely between
violet and magenta. The tertiary color that lies there is called
purple by Websters Dictionary and Roget's Thesaurus. Here are
the colors we'll discuss:
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primary blue |
indigo |
violet |
purple |
primary red |
Purple is nearest to red, and on the blue side of the middle
is violet, and indigo you'll find it is very near to blue. When
I was looking for other samples of office printer paper to show
you I found an interesting thing. These are all the commonly
available papers I could find between blue and rose:

| blue |
violet |
azure |
lilac |
lavender |
orchid |
purple |
mauve |
lilac |
rose |
I found that every manufacturer makes a paper on the blue
side, but only one manufacturer makes a paper called purple.
Between purple and rose I found few papers. Manufacturers always
say that they can only make what the customers buy because if
nobody buys a color they have to stop making it. Obviously very
few people want to use purple, and nobody seems to want purple-red
paper. Why is that? Fashion is always a factor, so maybe purple
will make a comeback in the future. But it seems to me that currently
people just don't really like purple when they see it. They may
ask for purple, but if you give them a choice of many colors
between blue and red they always pick the violets: the ones on
the blue side. |
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Steven M. Boker from a University Psychology Department writes
"Newton should be credited with the first model of perceptual
color space, essentially a color wheel with white in the center
(see Figure 1). This type of two dimensional slice through a
color opponent space has persisted in most formulations of perceptual
color representation to this day." for more read:
http://kiptron.psych.virginia.edu/steve_boker/ColorVision2/node4.html |
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How do we
see in color?
The Rochester Institute of Technology writes
"In the retina of our eye are photoreceptors that are sensitive
to light. When light is absorbed by the photoreceptors, the light
energy is converted into electrical and chemical signals that
the neurons in our eye and brain process. There are two kinds
of photoreceptors in the retina: rods and cones. Rods mediate
vision at lower levels of illumination. Cones mediate vision
at higher levels of illumination. There are three types of cones
with each type differentially sensitive to a different region
of the visible spectrum. They are known as the Long-wavelength
sensitive cones, the Middle-wavelength sensitive cones and the
Short-wavelength sensitive cones. Sometimes they are referred
to as R-, G-, and B-cones but these are misnomers based on the
colors in the spectrum. For example, very short wavelength light
can uniquely stimulate the B-cones but the sensation associated
with this light stimulation has a reddish and bluish component.
Fundamentally our color vision derives from comparisons between
the amount of light being absorbed by each cone type. Our visual
system compares the outputs of the cone types to process color.
In addition, color appearance is influenced by the ratios of
cone excitations in surrounding regions and by the overall levels
of cone excitation caused by the prevailing illumination. These
comparisons occur at different stages of processing that start
in the retina and continue to the cerebral cortex of the brain."
Read more at:
http://www.cis.rit.edu/mcsl/faq/faq1.shtml#q10 |
| Austen Clark writes "The
possibility that what looks red to me may look green to you has
traditionally been known as "spectrum inversion". This
possibility is thought to create difficulties for any attempt
to define mental states in terms of behavioral dispositions or
functional roles. If spectrum inversion is possible, then it
seems that two perceptual states may have identical functional
antecedents and effects yet differ in their qualitative content.
In that case the qualitative character of the states could not
be functionally defined" Those who love logic can read the
rest at: http://www.ucc.uconn.edu/~wwwphil/csolid.html |


Darren Meyer says "What
we perceive as color is really differences in the wavelength
of light. Many colors can be generated by a single wavelength
of light, such as red and green. Other colors can only be produced
by light containing a number of wavelengths, such as purple and
pink. To describe the wavelengths contained in a color a spectral
density curve can be drawn. This is a graph that has wavelengths
along the x axis and light intensity along the y axis. Colors
that are produced with a single wavelength have all their intensity
at a single spot on the x axis, while other colors contain a
mix of wavelengths. This is illustrated in the following diagram."

Read more at:
http://www.cs.wpi.edu/~matt/courses/cs563/talks/color.html |
However I think that the second graph that Meyer shows
above does not illustrate purple, because purple is not not a
collection of adjacent wavelengths but is made of colors from
the opposite ends of the x axis, something like this:
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HISTORIC DYES
Violet was originally from the flower Violacea: its color
is a dark blue red of medium saturation.
Indigo however is a dye C16H10N2O2 from a leguminous
herb Indigofera found in India whose color is very dark
blue with a coppery luster: I could only find one sample of indigo
paper:
Indigo
paper |
I believe that what Newton meant by indigo is what
modern engineers call Blue in the RGB system |
dark Blue in RGB |
Purple dye was always an expensive specialty. Near their port
of Tyre the ancient Phoenicians collected gastropod molluscs
of the genus Purpura that yielded the pigment. The Greeks
and Romans took a robe dyed purple to be an emblem of rank or
authority. Goethe reminds us that "The Roman emperors were
extremely jealous with regard to their purple"(840) and
made it against the law for other people to wear it. Purple still
signifies imperial or exalted rank. Even today this color is
worn by the popes and bishops. Here are names of various kinds
of purple: bishop's purple, imperial purple, king's purple, monsignor
purple, pontiff purple, regal purple, royal purple. These associations
with glorification and pride may provide a psychological reason
for common people to avoid it. As an adjective purple on the
negative side means obtrusively ornate, highly rhetorical, or
marked by profanity. |
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Bibliography of Tyrian purple:
Dyes in History and Archaeology
Kimura M, Sakamoto K, and Fujii H:
Studies on identification of the natural dyes on the textiles
from at-Tar caves al-Rafidan, 1993, 14, pp141-148. 2000 year
old samples of Kermes and Tyrian purple / indigo dyes on wool
are distinguished by UV/VIS spectra following extraction with
dimethylformamide and DMF-NaOH solutions giving wavelength maxima
at 550-600 nm (two peaks) and 600-620 nm respectively.
Taylor G W:
Detection of shellfish purples on textiles on Historical
and Archaeological Textiles, 1983, 2, pp20-21. Purple pigment
was extracted with pyridine, diluted with water and extracted
into ether. The ether evaporated and the residue taken up in
methanol for spectroscopy. Wavelength maxima in pyridine: indigo,
615 nm, dibromoindigo 605nm; in methanol, 610 and 600 nm respectively.
Read more at: http://www.chriscooksey.demon.co.uk/tyrian/cjcbiblio.html |
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FEELINGS
Of red-blue Goethe writes "Blue deepens very mildly into
red, and thus acquires a somewhat active character, although
on the passive side... It may be said to disturb than enliven.
... so we feel an inclination to follow the progress of the color...
to find a point to rest in. In a very attenuated state, this
color is known to us under the name of lilac; but even in this
degree it has a something lively without gladness. Blue-Red:
This unquiet feeling increases as the hue progresses.... On this
account, when it is used for dress, ribbons, or other ornaments,
it is employed in a very attenuated and light state, and thus
it displays its character as above defined, in a peculiarly attractive
manner. As the higher dignitaries of the church have appropriated
this unquiet color to themselves, we may venture to say that
it unceasingly aspires to the cardinal's red through the restless
degrees of a still impatient progression."(787-791)
A SCIENTIFIC REASON?
Looking at printing inks to see what the popularity of colors
is in respect to print, these are the only ready-mixed colors
I could buy between blue and red:
process
blue, reflex blue, navy blue, fast blue lake, violet, purple,
rhodamine red
Once again notice a plentiful range on the blue side, but a shortage
on the red side. Is there also a scientific reason for this?
Perhaps there is, because Websters largest dictionary says "As
analyzed in terms of appearance, most colors have a hue that
more or less resembles one of the hues in the spectrum.... The
purple hues, while not found in the spectrum itself, show a resemblance
to the blue and red ends and complete the color circuit."
(448).

So purple is not in the spectrum? How can that be? Don't scientists
tell us that we see by the light of the sun? So how can we see
a color that isn't there? But if the color spectrum is a straight
line becoming invisible at each end, how is it that we can join
the ends together by joining violet to red? The spectrum scientists
see from their prisms show that violet is the terminus, and if
you want to find red you have to go back to the beginning. So
purple doesn't make sense to a scientist because violet and red
are opposite extremes. However Newton's diagram clearly shows
that he believed that violet joins the ends together and it looked
OK to him. Thanks to this diagram all artists see the colors
in a circle not in a straight line, and the extreme differences
somehow become complementaries.
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CIE 1931
Chromaticity Diagram |
Charles A. Poynton
says "A color plots as a point in an (x, y) chromaticity
diagram. When a narrowband SPD comprising power at just one wavelength
is swept across the range 400 nm to 700 nm, it traces a shark-fin
shaped spectral locus in (x,y) coordinates. The sensation of
purple cannot be produced by a single wavelength: to produce
purple requires a mixture of shortwave and longwave light. The
line of purples on a chromaticity diagram joins extreme blue
to extreme red. All colors are contained in the area in (x, y)
bounded by the line of purples and the spectral locus."
Read more at: http://www.inforamp.net/~poynton/ |

Penstarsystems
says
"Cones are the second cell type, and these are much more
complex. There are three basic parts to them that absorb different
wavelengths of light and release differing amounts of different
neurotransmitters depending on the wavelength and intensity of
that light. Basically there are three receptors in a cone that
absorb red, green, and blue wavelengths of light. Each of these
receptors release a different neurotransmitter for the color,
with differing amounts of the neurotransmitter depending on the
intensity of the wavelength. Purple is a combination of blue
and red, so the red and blue receptors would release differing
amounts of neurotransmitter, while the green wouldn't release
any. This information then passes onto your visual cortex and
we "see" purple."
More at: http://www.penstarsys.com/editor/30v60/30v60p3.htm |
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THE CIRCLING DRAGON
We find this curious principle of consensus of contradictions
also recognized in the history of metallurgy. Following the Sumerian
observations from stars, in ancient Alchemical texts the seven
metals were synonyms for the seven planets:
| gold |
silver |
mercury |
copper |
iron |
tin |
lead |
| Sun |
Moon |
Mercury |
Venus |
Mars |
Jupiter |
Saturn |
Notice that the heaviest metals, gold and lead, are at either
end. Alchemists tying to make gold always put lead in their concoction
to give it the same great density that gold has. The elements
lead and gold are in fact very close on the modern scientist's
table of elements although distant at the scrap dealers. So the
early scientists were aware that the opposite ends of any aspect
of existence are similar in a strange manner. Indeed, the idea
for a circle of colors is first seen in Alchemical illustrations
of Ouroboros, the self-consuming dragon. This dragon was drawn
in a circle around the tangible world, eating its own tail, representing
how the beginning consumes the end. We should paint a dragon
with a magenta-head, a red neck, orange shoulders, a chest of
yellow, belly green, pelvis of cyan, hind legs blue and tail
violet.
This mystical circling is reminiscent of the twentieth Century
"doughnut theory" of the universe which conjectures
that if you could see far enough into space in one direction
you would see the back of your own head. This red head eating
its own violet tail is a metaphor for how the ends of the spectrum
could join into a circle. Modern scientists struggle to explain
how these two ends can meet. They say that below red's low frequency
lies infra-red, and above violet lies ultra violet, both extremes
being invisible frequencies to the human eye. It seems to me
that somehow this sharing of invisibility joins them in vision.
But considering that other creatures see wavelengths that we
do not see, we might conclude that purple is a product of human
eyeballs, not of nature itself. When we see a purple color either
we are seeing two visible colors overlapping, or two invisible
colors interacting to become visible. |
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WORKS CITED
All material on this website, unless otherwise marked, is copyright
©2002-3 David Kidd
Böhme, Jacob. Theosophische Werke. Amsterdam:
1682.
Boker Steven M. Dept of Psychology, University of Virginia.
The Representation of Color Metrics and Mappings in Perceptual
Color Space. Charlottesville <kiptron.psych.virginia.edu/steve_boker/ColorVision2>
accessed 24 Dec. 2002.
Clark, Austen. Department of Philosophy. University of
Connecticut. Spectrum Inversion and the Color Solid. Storrs,
1985. <ucc.uconn.edu/~wwwphil/csolid.html>. accessed 24
Dec. 2002.
Cooksey Chris: Dyes in History and Archaeology
1994 <chriscooksey.demon.co.uk/tyrian/cjcbiblio.html> accessed
27 Dec. 2002.
Goethe, Johann Wolfgang. Theory of Colors. Trans.
Charles Lock Eastlake. London: Murray, 1840. Reproduced Cambridge:
Massachusetts I. T, 1970.
Ishihara, Dr. Shinobu. Tests For Color Blindness.
<toledo-bend.com/colorblind/Ishihara.html> accessed
24 Dec. 2002.
Leslie, Sir John. Treatises on Various Subjects of
Natural and Chemical Philosophy. (59). quoted in Goethe Theory
of Colors (xxxii).
Meyer, Darren. WPI, CS Department. Color Theory and
Pre-Press
<cs.wpi.edu/~matt/courses/cs563/talks/color.html> accessed
24 Dec. 2002.
Penstarsystems, LLC The Human Eye (and Visual Cortex).
Laramie: <penstarsys.com/editor/30v60/30v60p3.htm> accessed
27 Dec. 2002.
Poynton,Charles A. What are CIE x and y Chromaticity
Coordinates? ©1997 <inforamp.net/~poynton/> accessed
12/27/02
Roget's international thesaurus. Ed. Peter
Mark. New York: Harper & Row, 1977.
Munsell Color Science Laboratory. Rochester I. T. How
do we see in color? Rochester: <cis.rit.edu/mcsl/faq/faq1.shtml#q10>
accessed 24 Dec. 2002.
Roob, Alexander. Alchemy & Mysticism. Köln:
Taschen, 1997.
Wilcox, Michael. Blue and Yellow Don't Make Green.
Cincinnati: North Light, 1987.
Webster's Third New International Dictionary. Springfield:
Merriam,1976. |
CONCLUSION CONFUSION
To go back to what we teach our children: "Roses are red,
Violets are blue, Sugar is sweet, And so are you" But why
do we say violet is blue? Is it because many people are color
blind and do not see the purple in the spectrum? Since purple
is made of red and violet, the colors on the extreme edges of
visibility, any disfunction or infirmity in our optical system
would be most likely to obscure purple. In conclusion other names
for purple make a list of precious stones, delicious fruit and
charming flowers. In enjoying these are we seeing beyond the
visible world?
| amethyst |
aniline |
burgundy |
clematis |
fluorite |
| red grape |
gridelin |
heliotrope |
hortense |
hyacinth |
| lilac |
livid madder |
magenta |
mallow |
mars violet |
| mauveine |
methyl violet |
mulberry |
orchid |
pansy |
| prune |
raisins |
sloe |
solerino |
Tyrian |
| crimson |
fuchsia |
lavender |
mauve |
plum |
| wine purple |
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(Roget 373.4) |
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