Your Yellow

Match true yellow light to a light source that mixes red and green, showing differences in colour perception.

How to Use It

Turn the wheel until the two light panels match as closely as possible. Lock it in and see how your perception of yellow compares.

What Science Tells Us

Our brain interprets input from our eyes to arrive at a perception of colour. Humans have only three types of colour-sensitive cell. One type is most sensitive to long wavelengths (red light), one is most sensitive to medium wavelengths (green light) and one is most sensitive to short wavelengths (blue light). Other colours—such as yellow—are the result of multiple cone types being stimulated at the same time.

Physiological differences between individuals—including number, density and spectral sensitivity of each type of cone cell—can affect how sensitive people are to each colour of light.

In this exhibit the true yellow light has a wavelength of approximately 580 nm. This stimulates both the ‘red’ and ‘green’ cone cells in a typical eye, however the degree to which each cone type is stimulated varies between people. This mean that when they are asked to match a mixture of red and green to true yellow their selection will fall within a range. People who fall to the edges of this range may have a colour vision deficiency.

Things to Try or Ask

Look at the coloured light panels through the viewfinder of a camera. Do they appear to match? Can you get them to match?

Have you ever disagreed with someone about what a colour is? Do you think this was related to a category error—such as defining where ‘green’ ends and ‘yellow’ begins—or a fundamental difference in colour perception?

Finding the Science in Your World

Digital displays in objects such as televisions and mobile phones take advantage of the fact our eyes have only three types of colour receptor. By stimulating each of these individually with red, green, and blue pixels, these displays can simulate almost all the colours we find in nature.