Modeling Color Spaces With Blender 35
Mrs. Grundy writes "When creative professionals want to visualize colors in three dimensions, they often use dedicated and sometimes expensive software. Photographer Mark Meyer shows how, with the help of its Python scripting interface, you can create graphics of color models in Blender. He demonstrates plotting in XYZ, LAB, and xyY space, and also includes the Blender file to show how it's done."
Deuteranomaly power :-) (Score:5, Informative)
Cool... now I can finally make a proper color diagram for my fellow deuterananomalous trichromats, scaled to maximize (and give proper names) to OUR gamut... including "dellow" ('deuteranomalous yellow' == our equivalent to "Unique Yellow" -- the color we see as having no hint of green or yellow. Some true deuteranopes have proposed calling it 'deen' -- deuteranopic green).
Since 94% of you are probably thinking, "wtf, 'dellow'?!?" right now, deuteranomaly is generally thought to occur when somebody ends up with 'green' cones whose sensitivity peak is closer to red than the stastical norm (with some semi-recent refinements theorizing that SOME 'protanomalous trichromats' might REALLY be atypical outright dichromatic deuteranopes with a mutation that gives us foveal rod cells to compensate and act like a third cone type under the right lighting conditions).
Anyway, for us, the part of the spectrum you call 'yellow' falls into a vast, bland ocean that's just plain 'featureless green' to us, and the color you call 'Home Depot Orange' is blatantly red, but we have a tiny zone sandwiched between them where moving a tiny bit left or right makes a HUGE difference to the color. Colors WE might call 'dellogreen' (greenish dellow) and 'dred' (reddish dellow), togerther with dellow itself between them would all look like kind of the same orange to you, but we could pick them out and name them as easily as you can differentiate between yellow, orange, and red.
Our colorspace and gamut are absolutely compressed and missing a few bits of depth, but it's made worse by the fact that digital cameras, monitors, and everything else samples or reproduces 'green' at the wrong frequency for us. The problem isn't that I need 'more green' to accurately capture and reproduce 'yellow', the problem is that mainstream hardware samples the wrong green, then squanders most of its bits into areas of the spectrum that are useless to us, and totally starves the tiny sliver where they'd do us the must good. We can talk about dellogreen, dellow, and dred, but trying to photograph/video them, then look at them on a typical RGB monitor (vs what you'd probably call a red-yellow-blue monitor, but we'd see as unambiguously red, green, and blue) would make them all look like 'dellow' to us, the way they'd all look orange to you.
I look forward to future pentachromatic imaging sensors with red, dellow, green, lumirod (the sensitivity curve of rod cells), and blue sensors, and tvs that natively do red-dellow-green-blue. Only tetrachromatic women would get the full benefit, but apparently the color I'm calling 'dellow' (deuteranopic yellow) is pretty close to the peak of a tetrachromatic woman's fourth cone, so we'd get a free ride out of the deal and finally get to have tvs that reproduce OUR gamut in its full possible glory.
Re:Deuteranomaly power :-) (Score:3, Informative)
Another interesting journal article about rod behavior in dichromatic individuals: http://macboy.uchicago.edu/~eye1/pdf%20files/large%20field%20tri%20josa%201977.pdf [uchicago.edu]
It appears that under specific lighting conditions, most deuteranopes CAN reliably distinguish between deep saturated red and pure green, even after controlling for relative brightness. The catch is, the color has to fill their field of vision, and they have to study & contemplate it in relatively dim light. In other words, they can't look at a blinking RGB LED on a dashboard and reliably figure out whether it's blinking red or green, but if they spent 15 minutes sitting in a dim room with black walls, then walked into an equally dim bathroom with vivid red or vivid green walls & floor (with brightness adjusted to a level that should, in theory, make the walls look "dark brown" regardless of whether they're red or green), the likelihood that they'd correctly identify them as red or green is greater than random chance would suggest. The explanation is that large areas of color would involve rods, but small areas would use foveal vision (which normally lacks them). I'm pretty sure this article influenced the other one I cited.
So, despite evidence like this, why does just about everyone take for granted that deuteranopes and protanopes have literally ZERO ability to discern red and green, ever, period, end of story? The partial limiting factor is cultural and cognitive... most people don't question the universe around them and feel compelled to constantly analyze and probe its boundaries. If an authority figure (like a doctor) tells them as a child that they can't tell the difference between red and green, and that everything they see is supposed to be blue, white, or yellow... most of them will take it at face value. Especially when they themselves notice that "red" sometimes looks distinctly different from green in their peripheral vision, tell someone like a doctor, and get smacked down & told they're just imagining things because it's impossible.
It's the colorblind engineers who start pulling out the lasers and studying them to see for themselves where the exact boundaries lie, and spend hours in dark rooms comparing the dim glow from a half-dozen $25 supersized infrared security camera floodlights from China to the dim green light from an Indiglo night light (a somewhat new phenomenon... up until a couple of years ago, there was no such thing as a source of 850nm infrared light that was cold enough to not act like an incandescent light, and bright enough to tickle just about everyone's cones enough to notice... if they were visible light, they'd be *blindingly* bright).
There's also another interesting twist to all of this... I haven't seen it officially documented, but if a rare deuteranope with foveal rods could end up passing for a somewhat odd anomalous trichromat, it seems like there's ALSO the possibility that a slightly less rare chromatypical trichromat who ends up with foveal rods might (emphasis on "might") end up with some degree of tetrachromatic color vision, too... and that most chromatypical trichromats might actually be able to learn to distinguish between "identical" metamers that are subtly different using their peripheral vision in dim lighting. It would be an example of some ability that's always been there, but nobody has ever really thought about, studied, or noticed because it would be so minor relative to their normal color vision that they'd only even become aware of it as a possibility after lots of personal experimentation and self-analysis. Of course, this would mean a tetrachromatic woman with foval rods might be able to experience pentachromatic vision under the same circumstances.
Anyway, fascinating stuff. :-)