I have heard mention that under some circumstances, black and white can appear to be in color. Not like a color photograph but more than black and white.
Today I’m getting my seating charts in order and they have small pictures of the students. They flash into the outside edge of my vision and the pictures has a distinct brown and red appearance to them. Think sepia photograph although not exactly. What is happening to give color to B&W pictures?
Benham’s diskmay provide some explanation, but according to wiki that’s not fully explained itself.
At a guess, it’s related to the distribution of rods and cones on your retina. Near the center of the retina, you have a lot of color-sensitive cones, but near the edges, it’s mostly the black-and-white rods. Thus, you’re used to seeing things, even colorful things, as black-and-white when they’re in your peripheral vision, and so your brain automatically fills in a color for them, since you “know” that it’s really color, it only looks black-and-white because it’s on the edge.
I bet Chronos hit the nail here.
Note that while we have few color receptors and mostly rods (“black-&-white” receptors) outside the fovea, we don’t seem to see in black and white in the periphery. The brain is using inference to add color where there isn’t sufficient color info coming in.
The effect is also called subjective color, Fechner color or PIFC (Pattern Induced Flicker Color). I started a thread on this elsewhere once:
http://65.69.77.33/forums/showthread.php?t=22925
Another commonly proposed explanation is differences in latencies for the response of the 3 types of color receptors. That sounds reasonable to me.
This TED talk demonstrates a variety of colour-related optical illusions. Of interest, approximately two thirds of the way through (8:20) are some cubes with grey squares on them that look distinctly blue in one case and distinctly yellow in another.
Colour interpretation is all about context and the bottom line is that humans are just not very good at it. We make inferences from the optical information we receive combined with the experience we have had and interpret colour from there.
I disagree: humans are remarkably good at it! We tend to see the correct color under a wide variety of conditions that make the sensory data misleading, such as widely varying lighting conditions.
We’re even better at inferring information about an object based on color shading.
The fact that we can be easily fooled with clever setups that take advantage of our built-in processing isn’t proof that we’re not good at it; it actually proves how good we are under normal circumstances.
Yes. It’s grey.
That is a contrast illusion, not a color one, but apart from that, no example of a color illusion would be a refutation of Learjeff’s point.
I think that’s what he’s talking about. That is a generated illusion designed specifically to trick our brains, because the illusion knows exactly what it’s doing to trick (I’m anthropomorphising, but you know what I mean).
Essentially, our brains are good at detecting color in the real world, but when put up against something designed to trick it, it’ll fail.
Doesn’t seem so far-fetched to me.
But that’s actually an example of what Learjeff is talking about. If you take a real checkboard and cast a shadow across it with lighting mimicking that illusion, your brain will correctly process the visual clues as indicating that all the light squares are objectively the same colour, and that the raw sensory data of the well-lit dark square being the same shade as the shaded light-square is misleading.
Back to the OP.
Do you wear glasses? Chromatic aberration can cause color fringes if you look at things through the edges of a lens.
Nope
As folks above surmised, that’s an excellent example of exactly my point: that despite the serious confusion of input data, in a real world situation, our brains assign the colors with remarkable accuracy.
The question our brains need to answer is not “What color is the light entering our eyes?” but “What color is the object?” It does quite a bit of work to answer it, too, as this lovely little illusion helps to illustrate.
I am going to reiterate my point. Our perception of colour is extremely context dependent and includes interpretation of many factors as well as visual cues. It seems that you agree with me.
My conclusion is that we cannot isolate colour information from other contextual information reliably.
Your conclusion seems to be that we are good at making useful comparisons in context. This may be true (or not). But it is not what I was referring to in my comment.
OK. I agree with what you meant, rather than what you said:
By “it” you meant “ignoring context”, not “Colour interpretation”.
It’s really a good thing that we interpret color based on context, because that’s how color appears in the real world.