Embedded Files
This section concerns the biological basis of colour perceptions, from retinal anatomy and physiology to conscious experience.
Two misconceptions, (1) that hues are physical properties residing in wavelengths of light, or (2) that hues are our perceptions of individual wavelengths of light, can each lead to the further misconception that hues inherently form the linear sequence that we see in the spectrum, and that we only arbitrarily bend this linear sequence into a circle. In fact, the hue of a light is our perception of an overall direction of imbalance in the spectral composition of the light relative to daylight, and these directions of imbalance have a 360-degree range, towards long, middle, short or long and short wavelengths. The spectral hues are are the ways in which we perceive a very strong imbalance towards a single wavelength, and thus comprise only part of that circuit; the non-spectral hues magenta and purple are the ways in which we perceive an imbalance towards long and short wavelengths. Hue circle adapted after DeValois and Webster (2011), Scholarpedia, 6(4):3073
Anatomical and Physiological Aspects of Colour Vision
Anatomical and Physiological Aspects of Colour Vision
Eyeball anatomy (AnatomyZone)
Superbly explained and illustrated video on eyeball anatomy and function.
Color vision (De Valois and Webster)
Exceptionally clear and authoritative overview of current colour vision science, including the physical stimulus for colour vision, trichromacy, cone opponency clearly distinguished from hue opponency, and spatial and temporal factors in colour vision.
Foundations of Vision (Brian Wandell, 1995)
Complete textbook, free to read online
A brief organized list (Brian Wandell)
Concise list of key facts about colour vision and its physical basis.
Human Color Vision (Robert M. Boynton, 1979)
Complete textbook, free to read online
Eye, Brain and Vision (David Hubel)
Complete 1995 paperback edition of David Hubel’s textbook, free to read online or download via Internet Archive Wayback Machine. The book is mainly about the development of Hubel and Wiesel’s ideas on how the brain handles visual information, covering roughly 1950 to 1980.
The joy of visual perception (Peter Kaiser):
Online book on vision including colour vision.
Webvision: The organization of the retina and the visual system (University of Utah).
Comprehensive medical website on vision science.
Seeing color through different eyes - Individual differences in human color perception (Michael Webster)
Outstanding webinar on the basics of human colour vision, individual differences in how we see colour, and the Implications of these individual differences for colour discrimination and colour appearance.
Color vision (Craig Blackwell)
https://www.youtube.com/watch?v=V73k_0KuUJo (Color Vision 4: Cones to See Color)
https://www.youtube.com/watch?v=VeDOpGRMZ7Y (Color Vision 5: Color Opponent Process)
https://www.youtube.com/watch?v=gH84_XipdNs (Color Vision 6: Color with 1, 2 or 3 Cones. In Humans and Various Animals}
https://www.youtube.com/watch?v=orwuGY5VQXQ (Color Vision 7: Primate Color Vision)
https://www.youtube.com/watch?v=8DGYsYU5yqQ (Color Vision 8: Opsins and the Evolution of Color Vision)
https://www.youtube.com/watch?v=ruKMIgmsUbw (Color Vision 9: Melanopsin in the Eye)
Unlike most video explanations of colour vision on YouTube, hue opponency is distinguished from cone opponency, although the usual convention of colouring the cones and cone opponent channels red, green and blue may still cause confusion.
The Science of Everything Podcast (James Fodor)
https://www.youtube.com/watch?v=CL4l1CUz1oU (Biology of the Eye)
https://www.youtube.com/watch?v=jXuIatjWzU4 (Visual Processing)
https://www.youtube.com/watch?v=SsiGzq1mrrc (The Visual Cortex)
From Introduction to Neuroscience (Bing Wen Brunton)
https://www.youtube.com/watch?v=dKcCscadzkg (Visual perception | Retina, photoreceptors, and rhodopsin)
https://www.youtube.com/watch?v=kN9lN9L8eKE (Color vision | Rod and cone cells in the retina)
https://www.youtube.com/watch?v=FjIcwZrPB78 (Visual Computations and Circuits | Receptive Fields | Sparse Coding Hypothesis)
Vision component of a series of very engaging and detailed videos on neuroscience. Very detailed on cone physiology and receptive fields; series doesn't cover colour opponency at the time of writing.
Why we're blind to the color blue (Caleb Kruse)
Explains using text and animations how chromatic aberration prevents the eye from focusing all wavelength of light at the same distance, leaving the short wavelengths unfocused.
Handprint (Bruce MacEvoy)
https://www.handprint.com/HP/WCL/color1.html#designeye (design of the eye}
https://www.handprint.com/HP/WCL/color2.html (the geometry of color perception)
Colour and colour vision: Background information (Colour and Vision Research Laboratories).
http://www.cvrl.org/ (follow link in menu on left under "Other Pages")
Novel color via stimulation of individual photoreceptors at population scale (Fong et al., 2025)
https://www.science.org/doi/10.1126/sciadv.adu1052
An attempt to activate M cones exclusively is shown to elicit a color beyond the natural human gamut, described as blue-green of unprecedented saturation.
Color appearance and the end of Hering’s Opponent-Colors Theory (Bevil Conway et al., 2023.)
A critique of the still generally accepted concept of unique hues by a leading neuroscientist.
The youtube theory of colour vision (David Briggs)
Examines how the seemingly harmless simplification of referring to “red, green and blue cone cells” inspired a suite of misconceptions that have become entrenched in popular explanations of colour vision, for example in This Is Not Yellow (Michael Stevens, 2012) and Colour Mixing: The Mystery of Magenta (Steve Mould, 2013). Unfortunately the model has infected some otherwise reliable resources, including Pixar in a Box's Color Science (Dominic Glynn) and several videos by Technology Connections (Alec Watson).
Physclips (UNSW)
https://www.animations.physics.unsw.edu.au/light/eye-colour-vision/index.html
https://web.archive.org/web/20250313115843/https://www.animations.physics.unsw.edu.au/light/eye-colour-vision/index.html (may be less slow than original link!)
Some Demonstrations Useful for Studying Perception (Greg C Elvers)
Hyperphysics (C.R. Nave, Georgia University):
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colviscon.html (Colour Vision)
Short pages on various topics related to colour, light and vison, set out in web arrangement
A splash of colour (University of Oxford)
Four short films on how we see colour .
The Optical Design of the Human Eye: a Critical Review (Rafael Navarro)
How the eye functions (1941)
Color Blindness – learn all about it (Colblindor)
Includes various articles plus online CVD tests and tools.
Online color challenge (Xrite)
Online colour vision deficiency challenge, based on part of The Farnsworth Munsell 100 Hue Test.
Isihara colour vision test
Vischeck
"Vischeck is a way of showing you what things look like to someone who is color blind. You can try Vischeck online- either run Vischeck on your own image files or run Vischeck on a web page. You can also download programs to let you run it on your own computer".
No such thing as color - What it's like to be color blind (Laura Evans)
Island of the colorblind (Oliver Sachs)
Ishihara and other colour vision tests (The College of Optometrists)
Tests for colour blindness (Ishihara)
Discussion of colour vision involves topics under three headings, (1) the physical stimulus (covered in part 2), (2) the anatomical and physiological aspects, and (3) the perceptual.
Perceptual Aspects of Colour Vision
Perceptual Aspects of Colour Vision
Handprint (Bruce MacEvoy)
https://www.handprint.com/HP/WCL/color4a.html (basic forms of color)
https://www.handprint.com/HP/WCL/color4.html (adaptation, anchoring & contrast)
Colorful notions (BBC, 1985)
Presents the controversial but stimulating ideas of Edwin Land who personally explains and demonstrates his experiments.
What art can tell us about the brain (Margaret Livingstone)
Lecture exploring connections between visual art and visual perception.
Colour constancy illusions and painting (David Briggs, 2018)
Striking illusions published by neuroscientists Dale Purves and Beau Lotto show something rather different to what Purves and Lotto claimed they show. The video examines these and other colour constancy illusions, what they do and don’t tell us about visual perception and how they illustrate a basic practical difficulty involved in painting appearances.
87 optical illusions & visual phenomena (Michael Bach).
Large collection of visual phenomena including numerous colour “illusions”, many of which can be explored interactively, accompanied by scientific discussion by vision scientist Michael Bach.
Akiyoshi's illusion pages (Akiyoshi Kitaoka)
Very extensive collection of original illusions by Professor Akiyoshi Kitaoka, continually updated since 2002. Recent additions also include numerous images and videos of most major colorimetric colour spaces.
Brightness illusion catalogue
Illusions and demos (Edward Adelson):
Adelson, E., 2000. Lightness perception and lightness Iilusion.
http://web.mit.edu/persci/gaz/gaz-teaching/index.html (Lightness Perception and Lightness Illusions) Interactive movies in Flash based on the Adelson paper. Can be played using Flash emulator Ruffle.
The illusions index (University of Glasgow, Centre for the Study of Perceptual Experience)
A dress rehearsal for vision science (Journal of Vision)
Special issue of the Journal of Vision on "The Dress" illusion of 2015.
The future of perceptual illusions : From phenomenology to neuroscience.
Optical illusions (eChalk)
http://www.echalk.co.uk/amusements/OpticalIllusions/colourPerception/colourPerception.html
Interactive version of some Purves and Lotto illusions.
Some more illusion sites:
The Illusion Contest channel
Psykinematix Widget Collection
It's not easy seeing green and Himba color perception (Mark Liberman)
An experiment on color perception among the Himba tribe of Namibia depicted in the 2011 BBC program "Do You See What I See?" appears to show Himba subjects who are unable to distinguish apparently very differently coloured stimuli that fall within the same colour category in their language but are readily able to distinguish apparently very similarly coloured stimuli that for them fall into different colour categories. The story has been repeated ever since in places like the New York Times and RadioLab. Curious to know why the experiment had never been published, linguistics Professor Mark Liberman in 2015 contacted the scientists mentioned in the episode and established that the film did not show an actual experiment but instead showed a performance "concocted for illustrative purposes" by the authors of the documentary and that the apparent experimental results acted out in the performance were not proposed or endorsed by the scientists involved. In actual experiments of the type shown, the targets used are normally one Munsell hue step apart (and thus neither wildly different nor indistinguishable), and the differences recorded are in the speed of recognition of the odd target, measured in microseconds.
"Essentially fraudulent" representation of experimental colour stimuli from the BBC "documentary" Do You See What I See? (2011)
Interactive Demonstrations
Interactive Demonstrations
Chapter 6. Color perception (Sage)
Good range of interactive demonstrations of colour vision, from the companion website to the textbook Sensation & Perception by Bennett L. Schwartz and John H. Krantz (2015).
Software for visual psychophysics: an overview (Hans Strasburger)
Huedoku (Gabriel Mott)
Assimilation grid illusion generator
Grayscale illusion
Project LITE - Atlas of visual phenomena:
Defunct site that had dozens of demonstrations of optical illusions and visual phenomena. Some of the demonstrations using Flash can still be made to work using Ruffle.
Google Sites
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