How does this light reactive painting work?

Light-reactive art works by manipulating how different colors of light interact with materials based on wavelength theory. Light is made up of electromagnetic waves, and each color has a specific wavelength measured in nanometers (nm). Shorter wavelengths (higher energy) correspond to blue and violet light, while longer wavelengths (lower energy) correspond to red and orange light.

For example, blue light has wavelengths around 450–495 nm, green light is about 495–570 nm, and red light is the longest visible wavelength at 620–750 nm. When light hits an object, certain wavelengths are absorbed, while others are reflected—and the reflected color is what we see. A red object appears red because it reflects light in the 620–750 nm range while absorbing shorter wavelengths like blue and green.

Now, if we change the color of the light in an artwork, it affects what we see. If you shine a red light (around 650 nm) on a blue object (which normally reflects 450–495 nm light), the blue object will look black or dark because no blue light is present to reflect. However, if you shine a blue light on a red object, it will also look dark because the red object absorbs blue wavelengths.

What is the visible light spectrum?

The visible light spectrum is the range of colors human eyes can see, from red to violet. It’s a small part of the electromagnetic spectrum, with red having the longest wavelength and violet the shortest. When combined, these colors form white light, like sunlight. We see colors because objects absorb some wavelengths and reflect others.