From Polaroid Pictures to Perception: Enter the world of Edwin Land's Retinex Theory
Red to orange, purple to yellow, then back again — when colors get weird, they tend to get extremely weird. Here we embark on a journey through the landscape of Retinex, the mind-melting theory of human color vision, conceptualized by the father of Polaroid, Edwin Land.
The story of Retinex begins in the early 1970s, when Edwin Land, amidst a flurry of research endeavours, patents, and innovations, found time to delve into the enigma of color constancy. This intriguing aspect of human perception showed the unchanging perception of an object's color, despite different light levels.
Confused? Well, picture the phenomenon of color constancy like this: you will perceive an apple as red, whether bathed in morning sunlight or shrouded in darkness at dusk. But why?
It all comes down to something called illumination context. Light illumination gives your brain the context to interpret what you see. So if there is darkness around something like an apple and the apple is darker, you will believe it is red instead despite its 'hex code' being something like dark blue.
Illumination context is crucial because the brain must work super fast to identify something; primitive humans needed to avoid dodgy mistakes when selecting food or encountering a predator. And given that color often signals peril in nature, the evolution of this perceptive system became a vital survival mechanism.
Elevating the art of seeing
After hundreds of experiments and demonstrations of color constancy, Land coined the term Retinex– a merging of the words 'Retina' and 'Cortex'. With Retinex, he sought to show how the brain and eye work together to show colors that aren't there.
Land noted that when we 'see' color, we actually notice the length of the light waves coming from what we're looking at.
For instance, seeing the color red could mean two things. You might be seeing the exact length of light waves that make up red, giving you the sensation of red. Or, you could see a combination of two different sizes of waves that, when mixed, create the same effect as red.
So, simply put, even if there's no red light, you can still perceive a 'red'. Trippy, huh?
Add this to the phenomenon of color constancy, and boom; suddenly, color gets seriously weird.
A round-up on Retinex
The explanation of the Retinex smashes our perception and unlocks a whole new world of color. Our latest film frames contain the same red dot, but our perception of this radically changes with each surrounding color combination. And you can harness Edwin Land's pioneering theory to bring your photography to life.
This article scratches the surface of the perplexing Retinex Theory. But if you're interested in diving deeper into the inner workings of the theory, there are a host of resources to look up online.
