The Physics of Color in Art
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Artist: Kaitlyn Daly

When you look at the painting above, what colors do you see? Red, green, blue, hints of white and maybe yellow. However, in reality you’re actually seeing what is the absence of those colors.
The colors that we see are referred to the visible light spectrum because they all lie between infa-red and ultra-violet, commonly known as ROYGBIV.
a color spectrum
a color spectrum

Electromagnetic radiation with wavelengths over 750 nanometers is called infa-red, and under 350 nanometers is ultra-violet, hence the colors red and violet.
Red wavelengths are longer and have a low frequency, and violet wavelengths are shorter and have higher frequencies. All of the colors visible to our eyes lie between the 350nm and 750 nm.

When each individual wavelength hits the retina in our eye, we perceive a certain color, because visible light is comprised of different wavelengths, or different colors. This separation of visible light is dispersion. When all of the wavelengths hit your retina at the same time, this results in the color white. Technically, white is not a single color, but a mixture of all the other colors’ wavelengths. Similarly to the fact that white is a combination of all the colors’ wavelengths, black is the absence of wavelengths.

The color that is visible to your eye not only depends on the wavelengths and frequencies, but on the ability of the object to absorb or reflect certain wavelengths and frequencies. Some objects may only be able to reflect red and blue frequencies, whereas another object can reflect red, orange, green, and violet. Reflection of light occurs when the frequency of the light doesn’t match the frequencies of the vibration of the object, similar to the resonance of the tuning forks in the lab we did.
Because objects are only able to absorb certain pigments, when viewing art, the colors that you are seeing in the painting are not the actual colors on the page, instead you are seeing the reflection of that single color or colors from the object. For example, see the picture below:
external image u12l2c4.gif

Creating other colors besides the primaries, red, green, and blue, you mix these primaries together to get the secondaries, tertiaries, and so on. This is shown by these pictures below:
external image u12l2d1.gifexternal image u12l2d2.gif

The history to this technique is fairly simple due to the fact that the pigments/wavelengths didn't change, the style of painting did. Something very interesting, though, is that at one point in time, artists would paint a picture by using extremely fine brushes, only painting one dot at a time. Up close the painting only appeared to be a series of colored dots, but when the observer took a step back, it was a beautiful piece of art.

In conclusion, the painting at the very top of this page was masterfully crafted by mixing the pigments of the colors, which creates a whole new set of wavelengths. This is how she created such different shades of blues, greens, reds, yellows, browns/tans, and even darker colors like black and grey. However, when we look at this painting we are not seeing those exact colors, but the reflection of that color. For instance, the blue background is blue because the paper in which she painted this piece on absorbed every other color and is reflecting the blue back to our retinas.

Physics at it's finest.