You can't believe your eyes: there's no red in this traffic light

Originally published at: You can't believe your eyes: there's no red in this traffic light | Boing Boing


“Brains trick us” is an interesting way to put it, instead of interpreting color according to context. Strictly there are no traffic lights or strawberries there at all, just pixels. But if there were they’d probably be red objects viewed through a teal haze…and in fact that’s exactly how these images were made. Good job recognizing that, brain!


Oh yeah!
And the color shift will persist for some minutes if you are exposed to a white-unbalanced light for a reasonable amount of time.
I discovered that in my early teen, using a red plastic soda cap as a monocle (don’t judge).
Once removed, I had a cyan shift on that eye, but even more surprising was that the uncovered eye definitely was red-shifted.

White-balancing pictures is a fine art, the brain does a pretty good job in real-life environments.


It’s not a red light, it’s quite clearly a blue dress.


I am very pleased that you eventually found your way here, where you will be accepted and never judged for that. Heck, we might even make you [non-gendered royal title] for it


i bet if they used black and white film those strawberries would not appear red.


All color is relative. I color comic books for a living and this is one of the first things I learned many years ago when digitally sampling a photo or reference and the color looking different when applied on a different background color.
I’d still argue that in context it IS red. But also There is red in that gray. If you had a monitor/screen that only produced blue and green pixels and no red you could not get that shade of gray. If you were ever a kid that pressed your face against an old tube CRT television and marveled at the RGB “pixels” (technically not but anyway) you’ll remember seeing how even colors that don’t seem to have red in them would have that red lit up when looked at up close.


I like traffic lights.
I like traffic lights.
I like traffic lights, that is what I said.
I like traffic lights.
I like traffic lights.
I like traffic lights, but not when they are red.

(sorry not sorry.)


In design class we did things like this with paint and putting either grays or other color around dots or squares of color to see how the perceived color would shift based on the color around it.


I’m so old I was taught about Land’s Retinex theory that the brain handles color so well, that one needs only two primary colors. The brain has an optical processing mesh of nerves for detecting motion. Apparently, it has another almost identical mesh for detecting color and maintaining color balance. Oliver Sacks had an account of a patient who lost his color vision and had to deal with the world exclusively in black and white. One thing about black and white vision is that intensities are changing all the time, even as one turns one’s head or light sources and shadows shift. Color, in contrast, stays relatively fixed. Intensity is absolute. Color is relative. That gives color a certain advantage in tracking real world objects.


This picture has NO red pixels. Great demo of color constancy (ht Akiyoshi Kitaoka)

GIMP says otherwise. If you mean no majority red pixels, sure. But red is certainly present in this picture.


Here’s the same picture with all “red” darkened to 0.


Mmmm…those snozzberries look delicious


My wife did graphic design and color is a complicated subject for her. When painting rooms we usually end up buying +6 sample jars and end up mixing and creating our own formula. Reflected light and color is very different from a colored light source (and even varying with what that source is). Our living room is a bluish color, but when sunlight comes in it appears more green. Evening sun can shift colors enough the original Behr paint color would look almost purple.

If you ask the person at the paint counter to make a color darker and they suggest adding “black” just walk away.


four lights GIF


I have Protanomaly, you insensitive clod! (wait… what website am I on again?)

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yeah! great minds think alike. here’s gimp on the stop-light itself. lots of juicy red pixels coming out of that red light region.


I dunno it looked grey to me regardless. I wonder if it would’ve looked red if I hadn’t been mentally primed for the result though.

Tricky, tricky brains …

… yep, and adding to that - it’s relative in some strange loop-like topology with non-real hues in the mix. Imagine how crazy it would be if hearing worked that way.

Ok, something is strange here.
This your image, in my Gimp:
Red is there, a bit more then G and B, much less saturated than your example.
Here my capture (using Firefox, a color calibrated monitor with sRGB profile, and Win-Shift-S) from the video:

Still slightly more red - depends where one picks - but still not strong as in your FG color window!
If you pixel peep your image, there’s some visibly red pixel.
If you pixel peep mine, they are much more uniform.

Whatever, I was just surprised from your numbers, can’t really say if the dress is blue/black or white/golden…

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Too true. Before the day is over, someone will bring up the relationship between brown and orange. :wink: Nooo - my childhood! :face_holding_back_tears:

Coloring Book Art GIF by PBS KIDS