Devin Korwin氏(@devinkorwin)の色についての解説ツイートより。


Part 1

Thread on color in painting! This will be a 3-part series with everything you ever wanted to know about color. What actually is color, and how do we use it? How come it is so hard to make a painting look natural if we start in black and white and then add color after?

絵画における色に関するスレッド! 今回は、色について知りたいと思っていたことを3回に分けて紹介します。色とは何か、どうやって使うのか?白と黒で描いた後に色を加えると、自然に見えるようにするのはどうして難しいのでしょうか?

Let’s start at the beginning with the basics in this thread. First, color is a 3D space that you could imagine yourself walking around in. We know this because there are 3 variables. If we plot only 2 of them, for example value and saturation, we can easily see that this is 2D.


This 2D space is familiar to us, we see it in the Photoshop/Procreate color picker. Once we add a third variable, hue, we have depth to our graph. Value is the amount of light, saturation is the purity of the light, and hue is the wavelength of the light (more on this later).


In this 3D space, hue loops around the outside. In Photoshop, hue is laid out as a strip, but it could be thought of as a continuous color wheel. When we change just value and saturation we are exploring a flat 2D plane, and when we move the hue we are moving through 3D space.


By lowering saturation, we are actually adding in the opposite, or complement, of the color. If we add blue to a pure yellow, it desaturates and passes through the land of grey, and then comes out the other side of the color world until eventually we get to a pure blue.


By desaturating blue, we are adding yellow, and thus making it warmer. This is why a greyer version of yellow is cooler, even though it is still technically a yellow hue. Temperature is relative, so we are comparing two colors to each other.


If we have a yellow object reflecting red light, we can walk around the edge of the world instead of going through the center. Instead, we could shift the hue and move through the oranges. It might even desaturate a bit because it is losing purity from the light mixing.


How do we know how far to move through the 3D color world? This depends on the materials and the intensity of the light. All that we see is due to reflection, materials determine the properties of it. A chrome sphere will strongly reflect the color of a blue light source.


A strong blue light on skin, with its unique material properties, will have the resulting color be pulled to the color of the light source but not all the way, resulting in pinks.



Thread on color in painting part 2! How do we know how to confidently decide on colors in the infinite lighting situations that we can imagine? We’re going to dive deeper this time into how light works, and what determines the color we actually see when light reaches our eyes.

ペイントにおける色に関するスレッドその2! 私たちが想像できる無限の光の状況の中で、自信を持って色を決めるにはどうしたらいいのでしょうか?今回は、光の仕組みと、光が目に入った時に実際に見える色を決めるものについて深く掘り下げていきます。

First, materials. They all reflect the scene, just differently. Diffuse materials absorb/scatter some wavelengths beneath the surface while reflecting the rest, some metals reflect all of the light, and others are colored due to uneven absorption and emission by their electrons.

まず、物質。すべての物質は背景を反射しており、単にその方法が異なるだけである。荒い物質は 表面下のいくつかの波長を吸収/散乱し 残りを反射しています。 ある金属は すべての光を反射しています。 別の金属は内部の(自由)電子による光の不均一な吸収と放出のために 着色されています。

The more pure and strong the reflection of the light source, the further the shift in color towards it. The direction of hue shifting depends on the material. A yellowy-green grass will travel through the greens when reflecting the blue sky, while skin will go through the pinks.


By knowing the material, the environment, and 3D structure of what we are drawing, we can make a good guess as to the colors. All color is due to reflection. Imagine what each plane “sees.” When a surface is no longer “seeing” the light source, it turns into shadow.


In this first example, the planes being lit are “seeing” and reflecting a light source that is relatively colder than the indoor environment. In the second, with sunlight, the white light of the sun looks warm compared to the blue influence of the sky. (sunlight is not yellow!)