colour wheelcolour wheel


I have been learning some groovy things about colour lately. I always knew that certain surfaces reflect and absorb various light rays in the spectrum. What I didn't know was that our brain reads colour as a set of ratios, rather than absolute values. So, according to neuroscientist Semir Zeki, green reflects 70% of middle wave (green) light and 20% of incident long wave (red) light, no matter what the amount of light. We compare all the values and the knowledge we get is about the reflectance of the various surfaces. Colour, according to Zeki, is an interpretation of that knowledge. [Semir Zeki, “The Neurology of Ambiguity,” in The Artful Mind: Cognitive Science and the Riddle of Human Creativity, Turner, Mark, ed. (Oxford: Oxford University Press, 2006) p.251]

Also, I learned a new phrase: scene gist. It means, guess what, getting the gist of a scene. We can do it really very quickly, and we can get scene gist even if we don't have time to identify any of the objects in the scene. Monica Castelhano has worked on the role of colour in scene gist. Structure tells us a lot, and so we can get the gist pretty effetively from black and white images. But Castelhano found that if the images are blurred, or the time they are shown is reduced, to the point where we have problems, then colour helps us out. One of the things that the brain does to be efficient is look for edges and boundaries, filling in surfaces automatically. Colour helps with this definition of shapes. But Castelhano and her team wanted to see if it had another role besides emphasising structure. They set up an experiment showing people scenes with natural colour, versus scenes with unnatural colour that nonetheless enhanced the structural qualities. People were able to get the gist better from the natural colour. [Castelhano, Monica, "The Influence of Color on the Perception of Scene Gist," Journal of Experimental Psychology: Human Perception and Performance, 2007]

From Semir Zeki, I also learned that we form a colour memory, learning from experience what colours are associated with what forms. Seeing natural colour in a natural environment activiates the hippocampus (which works on memory) and other parts of the brain that are involved with high level cognition. When we see abstract colours in a painting these areas are not activated. Says Zeki, "...abstract scenes do really seem to affect early visual areas without eliciting activity from areas which are active only when we view natural scenes." I'm thinking, though, that if we start trying to figure out what those abstract colours might mean, or whether our kid could paint that, then the frontal lobes are going to get involved pretty quickly.[Semir Zeki, Inner Visions: An Exploration of Art and the Brain, (New York: Oxford University Press, 1999) p.201]

- sally mckay 5-13-2008 4:16 pm

Reading colour in sets of ratios makes sense especially if you've spent any time pondering colour relationships.

Good work, carry on school girl.
- L.M. 5-13-2008 4:46 pm


don't I get a sticker?
- sally mckay 5-13-2008 4:56 pm


a big gold one
- anthony (guest) 5-13-2008 5:00 pm


a kitty one!
- sally mckay 5-13-2008 5:01 pm


dumptruck

A lesser scholar would just be doing all that work for some stupid degree on a stupid piece of paper.
- L.M. 5-13-2008 5:19 pm


Yay! thank you so much. Now I'm motivated...off to the library.
- sally mckay 5-13-2008 6:02 pm


"people were able to get the gist better from natural colour" I'm trying to figure out why this heartens me. Surely "natural" is all a matter of what we're used to. Ireland looks mega-green after eight days at sea. And there's that story of Alfred Hitchcock inviting everybody to a Thanksgiving dinner which he'd coloured blue (turkey, mashed potatoes, the works), and they couldn't eat it. My mom used to say that God knew we'd find blues and greens restful and that's why he used them so much in nature. Where to start, to pick this apart? But why am I relieved that natural colour is more effective for recognition? I got a flyer for vinyl windows yesterday that says, "The beauty of oak interior finish is available for select windows and grilles in a durable PVC laminate virtually indistinguishable from wood." Everything is trying to look real (cf. porkchop-shaped tofu). So I guess that's why I like the "natural colour" thing. It scores a point for really real, as opposed to fake real.
- M.Jean 5-14-2008 1:27 pm


Ah, the original six...(heh heh)...

Yesterday I was reading in some other reasearch on scene gist by Jennifer Steeves about a woman who had a rare disorder (from carbon monoxide poisoning) where she had lost the ability to recognise forms and objects visually. She found it easier to recognise natural objects, like fruit and vegetables, than fabricated objects. And she did pretty good at scene gist because she could still recognise colour and texture.
- sally mckay 5-14-2008 2:59 pm


Fascinating. My experience of this comes from having my vision greatly diminished by cataracts, to 20/100. I lost both colour and edges.I could not find a cervix with speculum exam, though I could easily find one with palpation. When my broken lenses were replaced with nice new plastic ones. colour and edge returned. Vaginal wall and cervix were the same colour, so that did not help, but with edges, the cervix reappeared. I said it before, but I am still amazed to discover that blindness can be a loss of edges and colour differentiation, rather than a loss of light.
- galenagalaxian 5-17-2008 3:55 am


Please note, dear readers, that our galenagalaxian is a doctor and not some random forensic perv.
- L.M. 5-17-2008 4:21 am





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