Simple answer: There is no physical basis, it's style
Pedantic answer: Unless the light source has different colors on different sides
Complex answer: Kind of. Even a linear color fade (from reality) can turn non-linear (and therefore induce color effects) when pushed through a color grading pipeline. So if you count e.g. film emulation as a "physical effect", then yes.
> when pushed through a color grading pipeline. So if you count e.g. film emulation as a "physical effect", then yes.
I've seen some footage from a particular Red camera body that introduced some very interesting effects. This particular camera had an issue with the Green channel. The camera was used in a commercial shoot for some fast food chain's shakes. The whip cream would turn magenta when the exposure was pushed because the green channel just wouldn't get there as fast as the red and blue channels. The secondaries had to go dig out extra green channel data plus other tricks to get the whip cream to end up white. After pushing other footage, the magenta tint could be seen else where as well.
TL;DR it's not just film emulsion issues where weird edge case things like this happen.
I think the effect the author is talking about is definitely caused by atmospheric scattering, but the painted effects are different. Those are more likely inspired by overexposure, aberration, HDR, etc. Makoto Shinkai specifically is a filmmaker and often emulates camera effects like lens flare.
It happens in reality, though I've only noticed it with desert sunlight. It's caused by light cast into the penumbra from scattering and diffuse reflection. You can't see this in the lit area because your photoreceptors saturate, which looks white.
This seems more like a chromatic aberration "hack" for HDR landscapes (intensely-lit portions of the scene would have color fringing apparent at the boundaries of light/dark due to dispersion in the observer's lens).
(And it's def a style choice, looks cool when done right! :))
Not sure it happens with the sun, but if you have differently located light sources of different colors you can get shadows of different colors (because the shadow area is one source being blocked but it is still illuminated by the other sources)
Came to ask this. I suppose if the edge of the sun glows in a different color than the rest, it would tint the edge of the shadow too? So maybe appropriate for sunsets, where the sky near the sun is red but the sun itself still glows bright white. Honestly just guessing.
The way I’m intuiting it: some things will “glow” when strongly illuminated, and the glow is more colored than the reflected light, so if the illumination has a hard edge then the penumbra can end up saturated by the more strongly illuminated part’s glow.
OP’s rendition isn’t quite landing for me, though, and I’m not enough of an artist to be sure why. Maybe it’s just that saturation is cranked way up for the demo, but it might also be that it shouldn’t occur on rock, or that color seems sometimes to not react to a change in which material is glowing.
What's the physical basis for this effect? Does it happen in reality or is it a style choice?
Simple answer: There is no physical basis, it's style
Pedantic answer: Unless the light source has different colors on different sides
Complex answer: Kind of. Even a linear color fade (from reality) can turn non-linear (and therefore induce color effects) when pushed through a color grading pipeline. So if you count e.g. film emulation as a "physical effect", then yes.
> when pushed through a color grading pipeline. So if you count e.g. film emulation as a "physical effect", then yes.
I've seen some footage from a particular Red camera body that introduced some very interesting effects. This particular camera had an issue with the Green channel. The camera was used in a commercial shoot for some fast food chain's shakes. The whip cream would turn magenta when the exposure was pushed because the green channel just wouldn't get there as fast as the red and blue channels. The secondaries had to go dig out extra green channel data plus other tricks to get the whip cream to end up white. After pushing other footage, the magenta tint could be seen else where as well.
TL;DR it's not just film emulsion issues where weird edge case things like this happen.
The post links another that goes into the theory a little: https://shahriyarshahrabi.medium.com/in-the-valley-of-gods-s...
Apparently a combination of Mie and Rayleigh scattering.
- https://en.wikipedia.org/wiki/Mie_scattering
- https://en.wikipedia.org/wiki/Rayleigh_scattering
I think the effect the author is talking about is definitely caused by atmospheric scattering, but the painted effects are different. Those are more likely inspired by overexposure, aberration, HDR, etc. Makoto Shinkai specifically is a filmmaker and often emulates camera effects like lens flare.
It happens in reality, though I've only noticed it with desert sunlight. It's caused by light cast into the penumbra from scattering and diffuse reflection. You can't see this in the lit area because your photoreceptors saturate, which looks white.
This seems more like a chromatic aberration "hack" for HDR landscapes (intensely-lit portions of the scene would have color fringing apparent at the boundaries of light/dark due to dispersion in the observer's lens).
(And it's def a style choice, looks cool when done right! :))
https://en.wikipedia.org/wiki/Chromatic_aberration
Not sure it happens with the sun, but if you have differently located light sources of different colors you can get shadows of different colors (because the shadow area is one source being blocked but it is still illuminated by the other sources)
Came to ask this. I suppose if the edge of the sun glows in a different color than the rest, it would tint the edge of the shadow too? So maybe appropriate for sunsets, where the sky near the sun is red but the sun itself still glows bright white. Honestly just guessing.
This page helped me understand what they’re going for: https://patapom.com/blog/Lighting/Colored%20Penumbra/Colored....
The way I’m intuiting it: some things will “glow” when strongly illuminated, and the glow is more colored than the reflected light, so if the illumination has a hard edge then the penumbra can end up saturated by the more strongly illuminated part’s glow.
OP’s rendition isn’t quite landing for me, though, and I’m not enough of an artist to be sure why. Maybe it’s just that saturation is cranked way up for the demo, but it might also be that it shouldn’t occur on rock, or that color seems sometimes to not react to a change in which material is glowing.
causes the external display I have plugged into my MBP (clamshell mode) to flicker quite badly
Cool!
FYI the arrows on both photos only actually control the top photo.