What creates the thin red pigment around the light and shadow

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What is called? Is that the reflected light or am I tripping?

Like if a round object such as a sphere is hit by light and shadow, there also appears to be this red tint around those. I’ve also seen it a lot in drawings but I don’t know how it works.

In: 7

I’m lost here. If you have a gray sphere sitting in a white environment and shine normal wavelength sunlight at it, you’re seeing red somewhere?

Situational. You’re probably thinking of an object with something red in the space that the object is reflecting.

It is diffraction.

Now slight changes on the colour happen because depending on the wavelength of the light (Unless you have perfect source of one wave of light) is made of many wavelength of light. Depending on the direction of light, the object casting the shadow and your eye, you can see slightly different parts of the spectrum of the light.

Basically there is diffraction grating happening.

If you have ever seen your eyelashes appear in your vision against bright light, you can see slight some colours at the edge of them. This is what basically what is happening.

But when it comes to art, to create shadow effects you don’t always have the choice to darken the colour you are using by adding black. In some mediums you don’t even have this choice. So if you want to make shadows you generally have two options, and you choose depending on the general pallet of colours you have; you can use blue or red. This is more obvious if you look at the [colour spectrum](https://en.wikipedia.org/wiki/Spectral_color#/media/File:Linear_visible_spectrum.svg). To make things appear darker and brighter you need to use colours cleverly. For example if you have really colourful painting, and you want to for example make a flame appear brighter, you might not want to add white to it since it might look off, well you can use slight amount of cyan or light blue, it stands off bright compared to the yellows and reds of the flame. This again is more obvious while you look [colour space diagram](https://en.wikipedia.org/wiki/File:CIE_1976_UCS.png).

A few things are going on here. It is important to remember light is a real thing interacting with the world around it. Just like an object blocks light where it is and doesn’t where it is not. Light interacts with edges of things. This is area is where something special different than the all or nothing of shadows happens. We call it Edge Diffraction. If the edge was sharp it would probably make a tiny rainbow at the edge of the shadow. In the case of round things with shadows we give the Edge Diffraction and even more special name of Creeping Waves. When you see “white light” what you see has every color of the rainbow in it. Each color behaves slightly different during diffraction. In sharp edges the light of different colors bend and spread out making that shadow edge rainbow. But for curves the light can ride that curve and bend or bounce. When it bounces back your rainbow gets confused and you can end up with missing colors. Often because of the room and world and our eyes you can and up seeing more red than anything.