Pixels And Art Glossary

[0xDB]

Where do these ideas of "warm" and "cold" come from though? ( I learned that stuff back in school I think but I forgot the origins and currently I am thinking it makes no sense to judge a color as warm or cold unless there is some psychological/art color model behind it. )

[AlexHW]

I think warm/cold are descriptive words for a type of sensation/feeling. Color corresponds to wavelengths of light, and the wavelengths are more or less intense for blue verses red, etc.. blue bounces more easily than red, so red feels more intense because it hits more directly. It may not be warm in temperature sense, but using that terminology is a way of translating the sense into something understandable I guess. There might be a better word for it?

[yrizoud]

Warm/Cold are defined and qualified as part of Color Theory : https://en.wikipedia.org/wiki/Color_theory#Warm_vs._cool_colors
The main reference linked by Wikipedia : http://www.handprint.com/HP/WCL/color12.html

[API-Beast]

Warm and Cold are the two opposite halves on the hue wheel.



As we know there are the three primary colors, Red, Green and Blue, our eyes are most sensitive to Greens, followed by Reds, then Blues. When we split the color wheel as above we have one side that has large amounts of blue in it (the "cold" side) and one side that has large amounts of red in it (the "warm" side), greens are equally present in both sides.

For the most time all light we had was based on fire, which falls on the red side of the spectrum, thus the "warm" and "cold" dichotomy. When we exclude modern light sources such as "cold" LEDs and computer screens then we can apply the general rule that lit areas are "warmer" and unlit areas are "colder", because during day the red wavelength of indirect sunlight gets absorbed by the atmosphere, and during night we have the red, fire based, light source.

[0xDB]

That is a lot of information to digest.

I also noted that it is sometimes very difficult to select and condense the most important bits of information/description of a term into a brief, comprehensible version. It might be a good idea to add links to wikipedia/other sources as "further reading" to individual entries in the Glossary.

[Ai]

On the subject of further reading: https://docs.krita.org/Gamma_and_Linear is a nice graphic illustration of color mixing, and particularly why painting with lowered opacity, or taking two sets of sRGB values and averaging them, is often not good (dull or outright wrong looking). Posted particularly for its relevance to 'Color space' and 'Ramp'. (GPick is a good tool for exploring color spaces, FWIW.. it also offers color scheme tools, which can be a help in understanding the warm/cool idea)

Warm and cold, AFAIK, are just this -- ranges of light wavelength. In practice, color wheels tend to be used to simplify things. However, the color wheel posted by Mr Beast is just one color wheel -- the traditional painter's RYB wheel. Modern digital art programs tend to use an RGB wheel (ie. based on additive, not subtractive color); the wheel produced by HSV / HSL is one example of an RGB wheel.

The 'color temperature' idea is similar but more or less reversed -- based on the visible appearance of stars and their relative temperature, AFAIK.

On a completely different topic: Where does line weight / balance fit into this? I was thinking about a few things, such as the contrast between

Code: [Select]

##..
..##


Code: [Select]

###
..##

And also the typographical concept of "Color", which is essentially what dithering aims to achieve, but is also a key part (whether in pixel, traditional, or more general CG art) of conveying impressions of relative size.

[Gil]

For the most time all light we had was based on fire, which falls on the red side of the spectrum, thus the "warm" and "cold" dichotomy. When we exclude modern light sources such as "cold" LEDs and computer screens then we can apply the general rule that lit areas are "warmer" and unlit areas are "colder", because during day the red wavelength of indirect sunlight gets absorbed by the atmosphere, and during night we have the red, fire based, light source.

Then why is a hot flame blue and a colder frame red?

The 'color temperature' idea is similar but more or less reversed -- based on the visible appearance of stars and their relative temperature, AFAIK.

But the hotter a star is, the more blue it is?

[API-Beast]

@Gil: We humans usually don't have access to blue fire, so our psychology and intuition says red = hot, blue = not hot. We don't compare red fire to blue fire, we compare red fire to the coldness of the (blue-ish) winter night.

[Ai]

The 'color temperature' idea is similar but more or less reversed -- based on the visible appearance of stars and their relative temperature, AFAIK.

But the hotter a star is, the more blue it is?

Which matches up with what you said. If you look at the linked chart, you see it goes red yellow white blue; this is as the temperature rises from 1000K to 10000K (usually temp is given in Kelvin for color temperature.)
(BTW, the quote above is of me, not Mr Beast)

I do agree with Mr Beast though. Red and yellow represent temperatures of burning material we can see close up without being flash vaporized

[Gil]

BTW, a blue flame does not flash vaporize you, a bunsen burner burns blue for example and you can hold your hand close to it without even getting burned. Cigarettes get up to 1100K (900° C) and they don't flash vaporize your nose

According to wikipedia, warm/cold colors seems to be a pretty recent thing (18th Century), so at the time, they must've had access to blue flames already. It's more a point of landscapes being blue if they're cold, red/yellow if they're hot apparently.