Light travels in waves as wavelengths. Some wavelengths are easier for humans to see, and green is the most visible from a distance. There are receptors in the eye called cones that contain pigments that sense wavelengths which communicate with the brain which colors we see.
The color green is most easily picked up during the day followed by yellow and blue. For that reason traffic lights are green and the color red is used as a contrasting color because there is so much green in nature. Red, however, is less visible from a distance.
Structures in the eye called rods help us to see during low-light situations and yellow is the most visible color from a distance in darkness. This is one reason why taxi cabs are often yellow.
In daylight the most visible color is one with a wavelength of 550 nanometers which is a color between green and yellow. However the surrounding environmental conditions need to be considered. This could be very important for joggers and cyclists. One highly visible color for safety reasons is fluorescent yellow-green. If you are outside running or biking during low light situations, consider choosing your clothing not only for rain and wind but especially for visibility.
In the 17th century, Sir Isaac Newton discovered that prisms can disassemble and reassemble light into various colors. Humans respond to light in the range of 380 to 740 nanometers. A nanometer is one billionth of a meter.
The gas neon was discovered in 1898. Gaslit tubing with neon was first presented in 1910 at the Paris Motor Show. The color glows as opposed to just lighting up and this is useful for signage, particularly at night. Neon is an invisible gas, but if an electric current runs through it in a glass tube, an orange-red color is produced. Other noble gases are used to produce a range of colors. The list includes mercury, argon, helium, xenon and krypton. The least reactive of all the elements, neon has very few uses except for neon lights.
Luminescent paint was invented in the 1930s. This of course promotes visibility in low light situations as well as from a distance. Pickleball colors are yellow, white, green, blue and orange. Therefore choosing a color depends on the surroundings, as the game is played inside as well as outside. Yellow is the most popular-selling color. Yellow has a wavelength of 580 nanometers. A single single piece of paper is about 1000,000 nanometers thick.
Water droplets in the air act like a prism creating a rainbow when the sun is behind you. The seven colors are red, orange, yellow, green, blue, indigo and violet. Red has the longest wavelength at 700 nanometers and violet the shortest at 380.