Color Is a Construct.
A field guide to the physics, perception, and poetry of light.
The Narrow Slice
Visible light is just a tiny fragment of reality—electromagnetic waves between 400 and 700 nanometers. Outside this window, the universe is dark to us.
Fig 1. Dispersion
White light enters the prism and separates into its constituent wavelengths due to varying refractive indices.
Snell's Law
n₁ sin(θ₁) = n₂ sin(θ₂)
The angle of refraction depends on the wavelength.
The Spectrum Plate
The continuous array of visible light, broken down by wavelength. An interactive spectroscope.
Spectral Power Distribution
Light is a distribution of energy. A single 'color' is merely the collapse of a complex high-dimensional spectral curve into our visual system's simplified three channels.
Fig 3. Interactive Plot
Draw on the chart to manipulate the spectral power curve. Observe how the final integrated color collapses down to a single perceived hue.
Integrated Output
Integrated Perceived Color
Reduction
Infinite spectral curves can result in the precise same perception. This loss of information is why metamerism occurs.
The Tri-Color Code
Your eyes are not cameras. They are chemical sensors. Three types of cone cells—Long, Medium, and Short—sample the infinite complexity of light and compress it into a three-dimensional signal.
Fig 2. Sensitivity Overlap
Opponent Processing
While the retina builds a trichromatic signal via three cone types, the ganglion cells immediately restructure this data into opponent channels: Red vs. Green, Blue vs. Yellow, and Light vs. Dark.
Photoreceptor Sensitivities (L, M, S)
Light enters the eye and stimulates three distinct cone populations based on wavelength. The raw signal is strictly positive.
Ganglion Cell Encoding
Signals are immediately subtracted against each other. It is physically impossible for a ganglion cell to signal both 'Red' and 'Green' simultaneously. Thus, there is no reddish-green.
The Grand Hallucination
Color is not a property of objects. It is a property of the mind. Your brain constantly recalibrates its sensors, manufacturing consistency where none exists.
Simultaneous Contrast
Our brains evaluate color based entirely on context. Use the slider to strip away the surrounding environment.
Color Assimilation
Conversely, foreground patterns can bleed into background colors. Slide the red and green stripes to shift their phase.
Color Constancy
The light reaching your eye is a multiplication of the object's reflectance and the room's illumination. Yet, a strawberry looks red at noon and at sunset. The brain actively 'discounts the illuminant' to perceive stable object properties.
Neutral, balanced spectrum.
Raw photons hitting the retina.
Metameric Failure
Two physical objects can have entirely different molecular structures and reflect different wavelengths, yet produce the exact same sensation of color. We call these 'metamers'. But move them to a new light source, and the illusion shatters.
The Topology of Perception
Mathematical distance is not perceptual distance. Changing an RGB value by 10 units might be invisible in the bright yellows, but violently obvious in the dark greens. We must distort physical space into 'perceptual space'—where distances align with human Just Noticeable Differences (JND).
Adding raw electrical signal (Green channel). Notice how slowly the Delta E (perceptual distance) climbs.
Structural Color
Not all color comes from pigments absorbing light. Some of the most vibrant colors in nature—the Morpho butterfly, the peacock feather—are produced by physical nanoscale structures that cause light waves to interfere and diffract.
Fig 7. Thin-Film Interference
When the microscopic lattice shifts relative to the viewer's eye, the geometry of the bouncing waves changes, causing different wavelengths to constructively interfere.
The Prison of Devices
The human eye sees a vast horseshoe of chromatic possibilities. Yet every device—your phone, your monitor, your printer—is trapped within a much smaller triangle of reproducible colors. This boundary is their 'gamut'.
Standard Web/Screen. Misses deep greens and cyans.
Psychophysics Laboratory
Color only exists because of the mind. Physics provides the stimulus; perception provides the experience. Let us perform three brief exhibits to probe the edges of your sensory apparatus.
Exhibit I: Limits
Tap the square that differs from the rest. As you succeed, the Delta E distance shrinks until it surpasses your visual acuity.
Exhibit II: Exhaustion
Stare deeply at the central cross for 15 seconds. Then, tap the canvas. You will see an afterimage born strictly from retinal fatigue.
Exhibit III: Linguistics
Where exactly does Blue end and Green begin? Language forces continuous physics into discrete cognitive buckets.
The Language of Light
Homer described the sea as 'wine-dark'. Certain cultures distinguish 'goluboy' (light blue) from 'siniy' (dark blue). We do not just see color; we read it through the lens of our language.
Appendix A: The Integrated Palette Exploration
This is Nova.
Thank you for visiting.
This project was inspired by the feeling of searching —
by the quiet beauty of “Searching for Birds” (Concept, analysis, design, and development by Nadieh Bremer | Visual Cinnamon),
and by my own curiosity about color:
its physics, its perception, its poetry.