Was working with some aircraft simulators/VR stuff, and wondered: I could tell if the light from the “outside” was real even if {I was wearing sunglasses, it is shady outside, I only had a sliver of my curtains open} but for some reason my brain instantly can tell VR/external street lamp lights as not real.
How come? What of the outside light (its not necessarily the wavelength only, since this happens with different colored lights outside as well) makes it seem more “real”?
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> (its not necessarily the wavelength only
I mean, it could be, sunlight is more broad spectrum than most artificial lights, especially modern LED lighting and even more so screens.
Sunlight is also considerably brighter than artificial lights, even when overcast.
I think it depends on what your brain knows to be “real” to begin with. The idea of real is a concept, you have always been taught “this is real” or “this isn’t real.” It’s maybe less that your brain recognizes something as real or unreal, and more that it recognizes something that’s one way and not another way. You can grow up in an artificial environment and never know anything about the outside world, and find outside strange when you see it for the first time. The same way your brain recognizes familiar flavours, or knows the sound of your child vs someone else’s, even if everyone is called “mom/dad”.
It’s less about the light, more about everything else in the vicinity. Real world lighting effects include all sorts of diffusion, dispersion, reflection, and other phenomena that simply put computers aren’t powerful enough to replicate in real time, or even close. Lighting is notoriously the hardest part of graphical simulation, and a huge part of the load of any sort of emulation, game, or rendering. The real world physics is just too complicated to accurately replicate, although with every generation we feel closer to replicating it, and it’s often not until the next generation that we realize how far off the current generation actually was.
A few motes of dust, semi-reflective textures like wall paint or a blade of grass, the blur of partial diffusion through glass, partial opacity, color blending, and a thousand other tiny context clues can make quite a difference in experience.
Sunlight is very broad spectrum, many artificial lights have a much spikier spectrum.
The eye itself can’t tell a difference between natural and artificial light that stimulates the cones and rods in the same proportion, but if you bounce them off of objects with different absorption spectra, they can look different under two lights that seem the same color when viewed directly.
With many lights, how well the spectrum approximates a blackbody is advertised as CRI(color rendering index), with an incandescent bulb being 100.