Move over imaginary numbers, there’s a new impossible-to-visualize concept in town: Imaginary Colors!
Stick with me here: Cone cells are the photoreceptor cells in your retinas that allow you to see colors. Human beings have three sizes of cone cells, logically named S (small), M (medium), and L (large). Each of these three is best at a particular range of wavelengths of light, and the combinations of how much each particular cone gets ‘stimulated’ by a light wave will determine the color you see. The color yellow, for example, is perceived when the L cones are stimulated slightly more than the M cones and not much activity happens at the S cones. Yellow!
So all colors are a combination of different cone responses. Here’s where things get wild: there are theoretical combinations of cone responses which cannot be generated by any physical light source! That means there’s colors that your eyes could see, but that no light could make!
I found out about this when I was working on a Photoshop tutorial and started reading about Lab color. Lab color is an alternate colorspace (ie not RGB like a monitor or CMYK like a printing press) designed to mimic the behavior of the human eye. But there are a lot of colors which are possible to create in Lab color which cannot be reproduced by your RGB monitor. Or by ANYTHING!
So are you salivating yet, over these new colors that you’ve never seen before? Wanna know how to see them? Yes you do! It’s easy. And a little disappointing, because all you can get is a limited, fleeting glimpse. Says Wikipedia:
“If a saturated green is viewed until the green receptors are fatigued and then a saturated red is viewed, a perception of red more intense than pure spectral red can be experienced. This is due to the fatigue of the green receptors and the resulting lack of their ability to desaturate the perceptual response to the output of the red receptors.”
I think I remember having that effect at a 5th grade Science fair after staring too long at a giant posterboard colored bright neon lime. As a final note, one last anecdote from Wikipedia:
“At Walt Disney World, Kodak engineered Epcot’s pavement to be a certain hue of pink so that the grass would look greener through the reverse of this effect.”
Maybe someday when computers have the ability to interface directly with our retinas, we’ll be able to “see” other colors… Maybe like an augmented reality style HUD or something. Or maybe just the most awesomest music visualizer ever. Hello, Institute of Shockingly Incredible Research That Sadly Has No Practical Value? I’d like to sign up for your Imaginary Colors program! ;)