Our Eyes Have Seen the Green and Red Light

February 16, 2023
By Alpec
graph of the human eye's relative sensitivity to wavelength colors

We have much to thank Sir Isaac Newton for – he formulated the theory of universal gravity and is called the Father of Calculus, for example. But from our laser-centric perspective, we’d also like to thank Newton for his work on defining the visible light spectrum.

ROYGBIV and the Visible Light Spectrum

From Newton’s experiments passing light through a prism, he identified the ROYGBIV (red, orange, yellow, green, blue, indigo, violet) colors that we all now learn in elementary school. Newton called this the visible light spectrum. The human eye is masterful at interpreting these waves and translating them into color.

The retina in our eyes sense light with light sensing cells known as rods and cones. While the rods are sensitive to the intensity of light, the cones sense the color. Three kinds of cones – red, green and blue – are each sensitive to a range of wavelengths within the visible light spectrum. Different rods and cones react to different wavelengths or colors.

The arrangement of rods and cones in our retina makes our eyes much more sensitive to green than to red. If you place these wavelengths or colors on a curve that shows how sensitive our eyes are to each color’s wavelength, green comes out on top every time. Check out our graphic, above, which maps out the human eye’s sensitivity to wavelengths, to see what we mean.

Applying this idea to lasers, we can say that green lasers are four times more visible to the human eye than red lasers of the same output power. As you can see on the chart, humans can see green across a vast swath of the color spectrum. You could even say our eyes are designed very well to see a range of green. Perhaps this is why green is one of the most popular color of laser pointer Alpec sells.

Is a Green Laser Pointer Right for Your Business?

Our basic green pointer, the Emerald Green Laser Pointer, is popular because it is so visible to our human eyes, 30 times brighter than red. Our eyes do that neat little trick with green and brighter can be good, especially over long distances or in challenging light conditions. But when choosing a laser pointer, red should still be a consideration. Even though our eyes are less sensitive to red, making red laser pointers less bright than green, red can do almost everything that green can do. And Alpec’s Spectra Red Laser Pointer pen is a high quality, durable laser pointer.  Or, choose the Emerald Duo Red and Green Laser Pointer. It offers the best of both colors in a single pointer pen.

Our Guarantee

No matter which laser pointer you choose, Alpec stands behind our products. Got questions? We’ve got answers. We are also keen to hear any jokes you know about wavelengths or rods and cones. We want to laugh at our own expense, too! Please send any laser pointer jokes our way and we promise to credit you if we post the joke to our blog.