AuthorTopic: How does the color of light mix ?  (Read 384 times)

Offline Xenon02

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How does the color of light mix ?

on: January 22, 2020, 10:09:20 pm
Hi !
I've been wondering because I want to create an effect that the source of light (like red LED) is reflecting from the wall, river, street etc. But how does it work ? I mean it's ok with White colors (presuming that the source of light is white or something like the sun), how does the red color mix with for example black ? How should I pick colors for the source of light ? (I think I shouldn't aim for colors close to purple that indicates shadows).

What do you think about this pallete (those above cube) is it appropriate ? How does it work with light side of the wall and how does it react with the darker side ?

Offline MysteryMeat

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Re: How does the color of light mix ?

Reply #1 on: January 23, 2020, 04:50:35 am
generally, all colors of light imbue a bit of that color onto whatever it's lighting. Ergo, a blue light will add a blue tint, an orange light an orange tint, etc.
PSA: use imgur
http://pixelation.org/index.php?topic=19838.0 also go suggest on my quest, cmon
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Offline Chonky Pixel

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Re: How does the color of light mix ?

Reply #2 on: January 23, 2020, 09:42:12 pm
When you're dealing with light, things mix in an additive way. If you keep adding different coloured paint, everything goes brown. Keep adding different coloured lights, you'll eventually end up with white.

Often with pixel art you'll have a primary light source and a secondary, or ambient source. A good example is an outdoor scene on a sunny day, with rocks. Rock surfaces pointing at the sun will be lit with white or yellowish highlights. The ambient light is blue (from the sky) so add some lesser blue highlights to areas of shadow. See Owlboy as an example:

https://i.guim.co.uk/img/media/65ddfa576ec0d5ba823cb8ab88383b829fc35c89/35_67_1064_639/master/1064.png?width=1920&quality=85&auto=format&fit=max&s=1ee98609b41e6e66bc4d3edb3ca52ac1

The theory is that without the direct light from the sun, everything would be blueish from the ambient light. (Don't start talking about how there wouldn't be any ambient light without the sun. Just don't.) The sun with its whiteish light gives us the natural shades from the rock. The ambient light is coloured and changes the hue.

This could work in other situations. Imagine a cave with lava (or orange walls) and a lit torch. Again the torch would give a direct yellowish/white light. The ambient light would be red/dark orange.

On a street, you might want to use some of the tarmac or pavement colours as ambient light, or reflected light from any large nearby surfaces.

Then there are other light sources. This should be obvious. If your object is in the way of something emitting green light (like an LED display or neon sign or something) then mix in some green highlights where you think the light will hit. Take into account whether you think the light source has the ability to overpower the main source of light in the image.

I don't know what you want to achieve with the palette. I'd have to see the context of the object you want to draw. Right now I'm not sure I understand your question properly.

Offline Xenon02

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Re: How does the color of light mix ?

Reply #3 on: January 23, 2020, 11:54:51 pm
https://pl.pinterest.com/pin/589830882433824106/

Paper is red but I don't know why but it looks more like there is more white color than red.

https://pl.pinterest.com/pin/134756213834486382/

It emit I guess red light, this steel tube is more grey than red, but If I look at it I don't know it just looks more like light grey.

I've seen somewhere a very good sprite where everything is dark, there is a red latarn and a very dark brown bridge (the bridge is more having a light brown color, instead of more light red)

I don't know how to explain it, when I tried it didn't give the same effect so I'm asking

Offline Chonky Pixel

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Re: How does the color of light mix ?

Reply #4 on: January 24, 2020, 01:39:48 am
Context is everything. In the first photograph there are lots of cues telling you that the light is pink from a sunset or sunrise. Look at the buildings through the window (especially reflections in the windows), the window frame, the highlights on the bottle, the patch of light on the desk. If the paper is pink it makes sense to read it as white because everything is telling you that the light falling on it is pink.

In the second picture, it's made obvious that the sign is glowing. All the surfaces nearby are tinted with the light coming from it, and the colour values make it stick out from the image. Again, we will read the nearby pink steel tube as grey because everything is telling us that it has pink light falling on it. In this case, we even have some tubing that isn't lit by the pink to inform us of the "real" colour.

This kind of context is very important to the way the brain reads an image. Putting a pink piece of paper in a scene without setting up pink lighting would give you a piece of paper that looked pink. Similarly, a pink pipe without the neon sign would also look pink.

Does this help at all? I may be misunderstanding exactly what your problem is.

Offline Xenon02

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Re: How does the color of light mix ?

Reply #5 on: January 24, 2020, 01:46:00 am
I think I've got it, I'll just try to have some fun with it first in some animations than in static sprites.
To find the issue in my attempts

Thanks !

Offline Chonky Pixel

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Re: How does the color of light mix ?

Reply #6 on: January 24, 2020, 09:49:19 am
Good luck!