Attached Link: http://www.echalk.co.uk/amusements/OpticalIllusions/colourPerception/colourPerception.html

Hi all.

If you are like me, many times you may have created a scene and wondered why the color of an objected just looked wrong. You'd go back in the material/ligh editor and everything looks fine but certain objects just look like they are colored incorrectly.

Well I found this website that shows how color perception may be way off based on the scene it is in. It is pretty wild. Just thought some of you may find this interesting!

http://www.echalk.co.uk/amusements/OpticalIllusions/colourPerception/colourPerception.html

The first one is particularly striking ! This effect is especially true for colors in the shades of grey, or very close to grey. They tend to mimic the colors in their immediate neighborhood. Thanks for the link !

• agiel - www.linfa.net

Wow, that will help me out much next time I tweak a color that doesn't seem able to change. Thanks

Message edited on: 08/01/2005 10:56

Didn't know I was that stupid! Didn't understand anything, didn't see anything either!

It's not a question of being stupid... it is just using a loophole in the way our visual system is designed.

• agiel - www.linfa.net

Thanks for the link. I'll be directing at least a few clients to that one!

That is really interesting. Hard to believe. I think the first one was the most interesting and hardest to believe. Great link - thanks

www.lingriffin.com

I also found these a few months ago and am using one in the eBook i'm writing for digital artists. Generally, our visual systems work remarkably well, but if you present just the right unusual stimulae things go way wrong. The fact that you have to build these very special visual experiences, called optical illusions, in order to experience the problems shows how well our vision usually works and how we have learned to compensate for the inevitable limitations. I think there is a lot to be learned from optical illusions - and they are a lot of fun too. That 3rd one is really amazing, must be new, since i didn't see it back then. Probably only works with yellow, which holds a special place in the spectrum, in that there are very few sources of actual yellow wavelength in nature. Most often when we experience yellow, it is from equal and strong stimulation of both red and green receptors at the same time. Pure yellow is such a narrow energy band that it usually doesn't have enough amplitude (brightness) to be seen as anything more than dark grey.

I agree, a very convincing demonstration of the fact that our senses aren't so much "recording realitity and absolutes" as "determining relevance and realitives". Another interesting example of the same principle (tactile, not visual) goes like this: You need 3 cups of water. One with rather hot (say, 45 C) water, one with cold (below 5 C) and one with room temperature (20 C). Now, put your left index finger in the hot water and the right in the cold one (or vice-versa, and use any finger you like etc.). Hold them there for about a minute or so. Then put the fingers in the cup with the room-temperature water. Now, tell me, can you trust your senses? I won't lecture on this, not the right place :) but the psychological implications are in fact immense, as the principle also applies to the way we interpret reality, depending of our past experiences and our present state of mind. You cannot trust your own judgements :)
Thanks again for this glorious link!

• Lars

Message edited on: 08/02/2005 13:09

Yup - you cannot trust your own senses (any of them). The body has various sensors, which send impulses to the brain. The brain then tries to interpret these impulses, according to what it already knows. The examples above are ways of tricking the brain: the "sensors (nerve endings)" see/experience one thing with absolute values, but the brain works with relative values, biased by the things that it "knows" are true, whether they are or not... Errm... I have several examples to expound upon this but my brian (misspelling intended) is a bit sleepy right now... (not to mention befuddled by certain alcoholic substances), so I'll leave it at that... Cheers, Diolma

Actually, as far as vision goes, a lot of visual processing happens in the neural networks built into the eyes themselves, before the electro/chemical signals even get to the optic nerves that then lead to the brain. I think of our senses as filters. An electronic information filter always leaves out much and also always leaves its fingerprints indelibly on the information it does pass. This is a large part of why our senses are not objective, but subjective. Understanding visual subjectivity and its effects gives visual artists some special abilities in their artwork.