José Ramón Isasi: "This is the best time of year to see the colors of nature"
Full Professor , from Chemistry and Associate Dean , from teaching , part of the School of Science , gave a lecture in which he explained the origin of colors in nature
13 | 11 | 2026
Why do we see colors? Where do the different hues in nature come from? These are some of the questions that Professor José Ramón Isasi answered during the“Science in Colors” lecture , held at the “ framework ”as part of Science Week.
More than 280 students from the following schools—IES Padre Moret-Irubide, CIP Donapea, Calasanz, IESO Elortzibar, Dominicas Pamplona, Sagrado Corazón, IES Sarriguren, and IES Julio Caro Baroja—have learned about the origin of colors and how we perceive them through a series of ten experiments. Among these experiments, Isasi performed chromatography on marker ink, demonstrated how hue, saturation, and lightness influence color perception, and explained how carmine is obtained from cochineal extract. She also presented the so-called “liquid traffic light,” a demonstration of the oxidation and reduction reactions of indigo, a natural dye.
Other experiments have demonstrated how red cabbage extract can be used as a pH indicator for household products, as well as to detect the fluorescence of substances such as quinine, riboflavin, and chlorophyll. In addition, he demonstrated the iridescence caused by light interference on a CD and recreated the colors of the sky and sunset using a mixture of water and milk. The session also included demonstrations on hemoglobin and artificial blood, as well as on the removal of synthetic dyes using charcoal. Finally, the professor presented some advances in the “ research ” of so-called “color proteins.”
Isasi also explained the pigments found in nature and the possibility of reproducing them artificially. “Ultramarine blue is a natural mineral pigment derived from lapis lazuli. We can produce the equivalent mineral artificially— laboratory —simply by mixing kaolin, sulfur, and pitch. With these inexpensive and simple reagents, we don’t consume many resources,” he explained.
He also highlighted the changes in color that trees undergo during the fall. “This is the best time of year to see the colors of nature. Trees—especially maples—change from green to orange, red, and yellow. And that’s because of the molecules they contain,” he said.