7 ago. 2013

The price of the color

During the night the eyes are dilated in order to try to see the objects around. All the things are in gray scale from light gray to black. There are no colors or at least, it seems to be like that.

In the next day, the rays from the sun allow us to see the colors. The balance between the light absorption and reflection of the objects let them to have a color. The color depends of the place of the world and also of the season. Nevertheless, paint a color is another story.

Painters have used colors since thousands of years ago. It is possible to see paintings in Altamira caves in Spain with old pigments in the rock. But also, it is not possible to see many colors used in that time.
Paintings through the history of art are the fingerprints of the materials available in each time and also a proxy of the materials price.

To make a painting nowadays, you have only to know the techniques and how to draw at least a little bit. In order to have the best results in you painting, you have to know about canvas types, brushes quality and kinds of paints with better quality and a longer duration. However, in past centuries, you had to know extra things like Chemistry and Physics and also you had to pay for the price of each color.
A pigment, a binder and a solvent are the necessary elements to produce the color on a surface (canvas, wood, rock, etc.). To extend the paint, the pigment is dissolved in water, oil or other solvent which will be evaporated afterwards. On the other hand, the binder serves to fix the color on the surface.

But, where the colors were from?

The color black was obtained from coal. The red color came from iron oxide (Fe2O3), sulfur and cadmium. The yellow and cream colors were obtained from iron oxide (Fe2O3) and chrome yellow ocher. The green came from chromium oxide (Cr2O3) and mixtures of copper and sulfur. The blue iron was obtained cobalt and sulfur. And the white came from titanium oxide (TiO2) and zinc (ZnO).
Other colors were obtained from other compounds and in order to have a great hue variety, primary colors were usually mixed.

Since we are kids, we are taught that primary colors are red, green and blue. However in painting, primary colors are yellow, cyan and magenta.

Why this difference?

From Physics, colors can be classified in spectral and non-spectral kinds. At the end of XVII century, Isaac Newton refracted the sunlight using a prism and obtained the 7 colors of the rainbow. These colors belong to the spectral kind. Further theories describe the light behavior as a wave and gave a frequency measurement in Hertz (Hz) to each color (red is between 405-480 Hz, orange is between 480-510 Hz, yellow is between 510-530 Hz, green is between 530-600 Hertz, cyan is between 600-620 Hertz, blue is between 620-680 Hz and violet is between 680-790 Hz. However other colors like magenta are not spectral but a mixture of spectral colors. This is the case of black (no color) and white (the mixture of all colors).
In painting, the selection of the primary colors depended of the facility for obtaining the pigments. The black is the mixture of all colors and in white canvas; the white color is the same of no color at all.

Through the history, not all pigments where easy to obtain and for this reason, the color of paintings are equivalent to its price to be made. Red pigment was very expensive and for this reason, it was the color of the clothes of kings and queens among other powerful and rich persons. Gold leafs, very expensive as well, were put to God, the Virgin and saints in religious paintings. However, the most expensive of the pigments in painting was the lapis lazuli or the blue gold as it was named during Renaissance. For that reason, it appears in valuable characters like Christ and Virgin Mary.
Today, synthetic alternatives to natural pigments have dropped the price of color but in the past, the color of a painting was directly related with the devotion of the painter or those who financed the artwork.

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