A page from the "Causes of Color" exhibit...

What are the sources?

Detailed References

This exhibit is inspired by and adapted from "The Fifteen Causes of Color: The Physics and Chemistry of Color," by Kurt Nassau. Wiley, 2001. This is a book that gives a detailed description of the underlying mechanisms of color, and provides a thorough grounding in the physical and chemical principles involved.


Overview Color vision in humans, and light spectra from "The architecture of the human color center," by A. Bartels and S. Zeki, European Journal of Neuroscience 12(1), 172-193 (2000). Some visual brain and Matisse quote from "Art and the Brain," S. Zeki, Daedalus 127, 71-103 (1998). Comments about fauvism from "Three cortical stages of color processing in the human brain," S. Zeki & L. Marini, Brain 121, 1669-1685 (1998). Philosophy of what is color, Arthur Schopenhauer, from "Splendors and miseries of the brain," S. Zeki, Philosophical Transactions of the Royal Society B. 354, 2053-2065 (1999). Microconsciousness in the brain from "Toward a Theory of Visual Consciousness," S. Zeki, A. Bartels, Consciousness and Cognition 8, 225-259 (1999). Some background on color from "Spectral Selectivity" by Ed Scott, 1997. Brightness constancy analogy (pieces of chalk and coal analogy) from E. Hering, "Zur Lehre von Lichtsinne," 1878, Carl Gerold Sohn, Vienna; translated in Fiorentini, et al, in Visual Perception (Spillman and Werner, Eds), 1990; via Werner and Ratliff, "Some origins of the Lightness and Darkness of Colors - in the Visual Arts and in the Brain," Techne, Number 9-10, 1999, Paris. Moreau and LePrince from Catching the Light: The Entwined History of Light and Mind by Arthur Zajonc, 1995. Kant quote from his Prolegomena. Descent from the Cross explanation from "Bloomsbury Guide to Art," by Shearer West, 1996. Some data about lamp energy requirements from Lighting Systems. Images and descriptions of various lamps in colored boxes from "Eyewitness Science: Light" by David Burnie, published by Dorling Kindersley (1992), p 52.

Background for shattuckite: The Science of Color by Steven K. Shevell, Optical Society of America. Definition of idiochromatic: Gem Select. Why minerals are colored, Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay. The origins of color in minerals by Kurt Nassau supports copper as causing blue color of shattuckite and transition metal compound as mechanism, American Mineralogist, Volume 63, pages 219-229, 1978.

Seeing color
In the eye

Seeing heat

Black body radiation:



platinum info, good source (PGI)

The Complete Book of Jewelry Making: A Full-Color Introduction to the ..., by Carles Codina

Color temperature:

The Complete Guide to Light & Lighting in Digital Photography, by Michael Freeman

Choosing Not Choosing, by Sharon Cameron

Color Influencing Form: A Color Coursebook, By Roy Osborne

Color for Science, Art and Technology, by Kurt Nassau

Lightbulbs and lamps
Flame tests

Colors of flame:



Candle in space


Color and Light in Nature, by David K. Lynch, William Livingston

Sprites and jets, red/ blue, Occur between top of cloud and ionosphere, diffuse in shape, narrow band emission from atmospheric atoms and molecules, esp excited nitrogen.

Lightning: Physics and Effects, by Vladimir A. Rakov, Martin A. Uman

Pictures (see pdf), jets, sprites, blue starters, elves


Vapor lamps

Aurora Borealis/ Australis

(magnetosphere diagram)

CME’s (coronal mass ejection from sun) > geomagnetic storms, particles collide with atmospheric particles, emit light analagous to TV screen phosphorescence

cutaway magnetosphere

Good background and pictures

Great photographs and photography hints

Auroras elsewhere in the solar system

Auroras differ at the two poles more than expected

Equinox auroras

Auroras- Folklore

Summary of quotes below:


Bad weather, souls of virgins dancing, Bifrost bridge to heaven, Finnish burning river Rutja, warrior reddening (prep for battle) Finnish name ‘revontulet’ means firefox, sparks brushed from fox’s tail, foxes of fire in Lapland, Norse chronicle of 1230: 3 possible explanations: that the ocean was surrounded by vast fires, that the sun flares could reach around the world to its night side, or that glaciers could store energy so that they eventually became fluorescent.Flash from shoals of herring. (Also from ice, Icelandic geysers or volcano) Norway: respect and don’t stare at them. Reflections from shields of the Valkyries, women serving the god Odin who led slain warriors to his side. Viking goddess Freja on horseback, seen as glow by mortals.


Football, souls with walrus skull (Greenland) or walrus souls with human skull (Nunivak island), whistle attracts, handclap repels, good weather, at Point Barrow wore knives in self-protection. Hudson Bay: torches to guide souls through the holes of the sky’s dome to heaven. Highest level of heaven, place of good weather where food is easily caught. Among some Greenlander Eskimos, the aurora is thought to be caused by the spirit of stillborn or murdered children playing ball with their afterbirths. The Copper Eskimos view the aurora as the manifestations of the spirits that bring fine weather. Whistle: imitates ‘sound’ of aurora to call dead spirits.


Lanterns of spirits Seeking or guiding souls to heaven; Fox Indians: souls of dead enemies, feared. Others – fires of powerful medicine men up north. Algonquin: ancestors dancing round fires, or Nanahbozho, creator of the Earth, who made fires in the far north to remind his people he remembered them, reflecting as aurora. Klondike gold diggers: reflection of great gold lode. Both as sign of continuing battles of violent deaths, also as omen of coming birth.


Name from Roman goddess of dawn, Aurora. Aristotle: appearance of flames of burning gas. Soldiers fighting on in afterlife. St George may have battled aurora not dragon. Greeks and Romans: chasmata, mouths of celestial caves→ isochasms are locations with the same auroral occurrences. British isles: ‘nimble men’ or ‘merry dancers’, red was blood spilt when they fought each other. Estonia: spirits of higher realms, games played by whales, even a crocodile is involved. . Sami: would attack if provoked, required respect. Latvia: omen of coming evil, famine or war. Russia: fire dragon that seduced married women.

AUSTRALIA – Gods dancing


Serpents, dragons

MODERN MISCONCEPTIONS – reflections off polar ice, audible as crackling and hissing – not proven

Auroras-The Cause


What color is Water

Scientific proof why its blue

NASA reference on true colors as seen from spac

Colors from vibrations

Scientific theory on why water is blue, vibrations and D2O vs H2O, Primary source for details of vibration mechanism

The Science of Color by Steven K. Shevell, Published 2003, Elsevier, ISBN 0444512519

Most molecular vibrations are in thermal range, water has a higher, visible light wavelength vibration because mass is small and bonds very strong. Describes 3 fundamental vibrations plus overtones in UV.

Color for Science, Art and Technology by Kurt Nassau, 1998, Elsevier, ISBN 0444898468

Agrees very closely with Shevell (Shevell copied Nassua I think)

High-level discussion of H-bonding and vibration-rotation

Light and Color in the Outdoors by Marcel Gilles Jozef Minnaert, 1993, Springer, ISBN 0387979352

Discusses variation in shade, roles of weather, impurities and reflection; attributes intrinsic blueness to scattering

Snow and ice

No credits

Colors from bacteria

A Memorial of Egypt, the Red Sea, the Wildernesses of Sin & Paran by George Fisk, Carter, 1850

Definition of phycobilin, blue-green and red algae, probably not needed, discusses cyanobacteria

discusses cyanobacteria (prob not needed)

Phycoerythrin (prob not needed), protein used by algae in photosynethesis, reddish color

Archaean – Proterozoic eras


We said “Although a lot of references are listed below, we did not find them all to be credible and some confused the issue, but they have been put in for completeness. “?

Scientific paper- Discuss optical properties of gold related to free electrons, discussion of energy band structures

K Saeger and J Rodies, The Colour of Gold and its Alloys, Gold Bulletin, 1977,10, 10

Scientific paper- Discuss colored gold alloys, yellow, red, green, white, purple gold and color and band theory

C.Cretu and E.van der Lingen, Coloured Gold Alloys,, Gold Technology, no 30, p31

blue gold (can lose as is covered off above better)

Scientific paper - Discusses origins of color in minerals, in particular band theory

Kurt Nassua, American Mineralogist, Vol 63, pages 219-229, 1978

Band theory of solids, discusses quantum physics

band theory (brief descriptions)

background info on gold and color

Purple of Cassius (color in 18th century, glass)

Optical properties of gold nanoparticles


No credits

Diamond and semi-conductors

Halliday and Resnick, Fundamentals of Physics

Extended Third Edition, 1988

John Wiley & Sons

ISBN 0-471-63736-X

Richard Tilley, Understanding Solids: The Science of Materials

First Edition, 2004

John Wiley & Sons

ISBN 0-470-85276-3

Diamonds structure

band structure of blue and yellow diamonds

The Physics and Chemistry of Color: The Fifteen Causes of Color by Kurt Nassau

Color, A Multi discipliniary approach, Heinrich Zollinger, Wiley-VCH, 1999

Doped semi-conductors

Additional applications of LED’s

Good explanations of semiconductor behavior


The Physics and Chemistry of Color: The Fifteen Causes of Color by Kurt Nassau

Color, A Multi discipliniary approach, Heinrich Zollinger, Wiley-VCH, 1999

Colorless Gemstones

Nassau, The Physics and Chemistry of Color

Williamson, Light and Color in Nature and Art

Red ruby

Nassau, The Physics and Chemistry of Color

Williamson, Light and Color in Nature and Art

Green emerald

Nassau, The Physics and Chemistry of Color

Williamson, Light and Color in Nature and Art

Blue sapphire

The Science of Color By Steven K. Shevell, Published 2003, Elsevier, ISBN 0444512519

Blue sapphire mechanism, charge transfer in sapphire why blue

This article suggests evidence is insufficient for charge transfer effect in magnetite,

Evidence for removing blue tanzanite from this section

Tanzanite crystal field

Mineralogical Applications of Crystal Field Theory By Roger G. Burns, Contributor Robert C. Liebermann

General info on sapphires as gems and different colors

Determine if gem heat treated

Heat Seeker: UV Fluorescence as a Gemological Tool, By Richard W. Hughes & John L. Emmett, ruby-sapphire.com

Readings on Color By Alex Byrne, David R. Hilbert, Published 1997, MIT Press

Chapter 1: The Causes of Color (K. Nassau), ISBN 0262522314

colors from metal ions


Readings on Color By Alex Byrne, David R. Hilbert, Published 1997, MIT Press

Chapter 1: The Causes of Color (K. Nassau), ISBN 0262522314

The Science of Color By Steven K. Shevell, Published 2003, Elsevier, ISBN 0444512519

colors from metal ions

lecture notes

Plants & Flamingoes
Plants & colored organic molecules

Good reference to dyes and colors and organic chem. (double bonds)

Color from molecular orbitals, Color for Science, Art and Technology, K.Nassau

Color from molecular orbitals, The Physics and Chemistry of Color: the 15 mecahnisms, Steven Shevell

Indigo and Ancient Egypt

Chemical formula of organic compounds




Hair dyes:

course notes-organic dyes

Green Plants

Chlorophyll absorption spectrum

Chlorophyll gen info

Many types of chlorophyll and description

Uses of chlorophyll as dyes, pigments etc.

More uses of chlorophyll:


food, industry


medical cosmetics


solar energy from spinach and toothpaste

extra phthalocyanine

Fall & Fruit

Chemistry of autumn colors

Why maple leaves change color in Fall (chemistry)

general overview chlorophyll, carotene, lycopene




Overview types of flamingos and what they eat etc.

Bristol Zoo, - carotenoids in tiny shrimps they eat

Sandiego Zoo, how different types of flamingoes eat, suck through mouth

San Francisco Zoo, add canthanthin to diet as well as caretenoids

Discuss fish farms and addition of astaxanthin and answers by various scientists

Colors of salmon measured

Cyanobacteria; article on pollution related deaths in Africa, some pics too

Color charts for soil, salmon, maple syrup etc. Only a brief allusion to flamingo diet, but interesting,



Colour: Art & Science Edited by Trevor Lamb and Janine Bourriau, Cambridge University Press, 1995

The Nature of Light and Colour in the Open Air by M. Minnaert, Dover Publications, 1954


Good but simplified explanation

Good explanation on cause of rainbows, size of drops → purity of colors, very fine drops produce a white bow (fogbow)

Introduction to how rainbow forms, no mathematics, great pics

Refers to ancient studies of rainbows, licensed to University of Chicago Press

Points to ancient texts describing refraction and not just reflection as the mechanism

Need to search within http://links.jstor.org/

Isis, Vol. 47, No. 4 (Dec., 1956), pp. 383-38

Refraction and the Rainbow in Antiquity

Carl B. Boyer

Dispersive Refraction

Background on green flashes, An Introduction to Green Flashes by Andrew Young, 2002 – 2006

Excellent descriptions of basics of optics and refraction

Ice haloes and related phenomena; great images

German club for atmosphere effect enthusiasts, "Arbeitskreis Meteore e.V." (AKM)

Course on gems

Famous diamonds- Centenary Diamond,

Chromatic aberration in Venus



Excerpt from "Exploration of the Universe" by Abell, Morrison, and Wolff, 5th edition

Newton’s telescope from

chromatic aberration

Blue or Black Sky

Argues against blue scattering in plant kingdom. It is extremely rare, if found at all.

Schemochromic Blue Leaf-Surfaces of Selaginella

Denis L. Fox, James R. Wells

American Fern Journal, Vol. 61, No. 3 (Jul. - Sep., 1971), pp. 137-139

Blue & red

Rayleigh scattering

Educational site on why sky blue

Example of scattering, adding milk to water

Animation on scattering

Excellent animation on electromagnetic wave propagation:

Earth shadow

Fundamentals of Atmospheric Radiation: An Introduction with 400 Problems, By Craig F. Bohren, Eugene Clothiaux, Published 2006 Wiley-VCH, ISBN 3527405038

Color and light in nature* , by David K. Lynch, William Charles Livingston

Atmospheric Pollution: History, Science and Regulation by Mark Zachary

Twilight and anti-twilight arch

Color of sunsets

The effect of pollutants on sunset colors


Background and photos from Mars missions

Blue eyes

Use of Raman spectroscopy in paintings, Rosy discoloration by another name by David Bradley, SpectroscopyNow, Nov 1, 2007


Iridescence: Platt, Meridith E. 1996. Iridescence in Insects. Milwaukee Public Museum; Tada, Haruna et all. 1998. Effects of butterfly scale on the iridescent color observed at different angles. Applied Optics. Vol 37, # 9, March 20, 1998.; Vulinec, Kevina. 1997. Iridescent Dung Beetles: a Different Angle. Florida Entomologist. Vol. 80, No. 2: 132-138.; Wu, C. 1997. Butterfly Sparkle Characterized for Chips. Science News Online.


No credits


general overview

General info on pearl (can probably lose this or at least some of them)

Structure of nacre (detailed scientific papers)

Mother of Pearl, nacre structure

Mother of Pearl properties

Analysis of nacre (scientific papers)

Colors in pearls and shells caused by diffraction & interference (scientific paper)

Full article on diffraction grating effect in mollusc shell

The mineralogical microstructure of shells: Part 2. The iridescence colors of abalone shells. American Mineralogist Vol 90, p 1705-1711, 2005, M. R. Snow and A. Pring

Iridescence from Bragg diffraction of light from layers of nacre. Locally even thickness of tiles, compares with opal POC.

iridescence, interference

Shell color by Diffraction

Shell color by Diffraction, iridescence



Conchiolin and chitin

Violins and Mother of Pearl


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Recommended reading or further links on fun with bubbles

Bubble science

Bubble performing arts

Photoelastic stress analysis

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How do things look

Tritanopes can have problems distinguishing yellow from violet. Can have pink, orange and brown confusions.


Vision simulator

No credits

Causes and incidence

Tritan defects inherited or aquired during lifetime

Educational site, color vision deficiencies

Color vision deficiencies, good reference to Blue cone monchromacy

Scientific paper on Molecular Genetics of Color vision and Color Vision Defects by M, Neitz and J.Neitz, excellent read

Scientific paper on Molecular Genetics of Color Vision Deficiencies by S.S. Deeb

Scientific paper on Visual Pigments and Molecular Genetics, J.K. Bowmaker


No credits


Lund University: images, discussion of fields currently under research

Neuroscience for kids: ‘amazing facts’ by animal (ordered alphabetically)

Comparison of visual systems across animal kingdom, detail and images of ommatidia, Snake: thermal pits


Great detail on vision and color vision in birds, lots of images and references, Nervous System: Brain & Senses II

Owls and their specializations

Bird, cat and dog vision compared with ours

Husband, S. & T. Shimizu. 2001. Evolution of the avian visual system. In R. G. Cook (Ed.), Avian visual cognition (On-line). Available: www.pigeon.psy.tufts.edu/avc/husband/

(Bristol University) Tetrachromacy as 4-D color; bees are shifted trichromats with UV instead of red. Interesting comments on how our color perception has affected our study of behavior and evolution, until recently it was assumed that human vision was the ultimate. Differences in how birds see each other have only become apparent to us recently and form a current topic of research, for example in mating behavior

Rowe, M.P. 2000. Inferring the retinal anatomy and visual capacities of extinct vertebrates. Palaeontologia Electronica 3(1).

Birds: field of vision, binocular vision, rods and cones for diurnal/ nocturnal birds, double fovea


No credits

Color Mixing

Principles of Color, Faber Birren, 1987

Energy of Color

No credits