What are the most reflective colours?
As light hits a surface, some of that energy gets absorbed and some of it is reflected back off the surface. When a person sees a colour, what they see is dependent on wavelength that is being reflected. White contains every wavelength of the colour spectrum, so when white is reflected, this means all wavelengths are being reflected with none being absorbed. Therefore, white is the most reflective colour of all. This explains why hazard markings and vehicle livery combines white, yellow and orange as it’s the easiest to see from a distance. For more information on Chapter 8 Chevrons, visit https://www.vehiclechevrons.com
With electromagnetic radiation, light moves in waves with some colours having longer wavelengths than others. The light that we perceive as being white contains the whole rainbow of colours in the spectrum that goes from blue to red, with yellow, orange and green coming in between. The colours of blue and violet have short wavelengths and higher energy, with red being at the other end of the spectrum and having long wavelengths with less energy.
When a surface colour is something other than white, that means that is absorbing some light wavelengths. For example, a red surface will absorb green, yellow, blue and violet light, but reflect the red. Similarly, a green object will absorb all colours but not green. White, as we’ve already mentioned, is a combination of all colours and this becomes apparent if you shine a light into a prism. Any object that appears white will have the ability to reflect all light wavelengths. The least reflective colour of all is black, which absorbs all light wavelengths.
Even if a surface or object isn’t pure white, the closer it is to white, the more light that it reflects. For example, off-whites and pastel shades will reflect more light than deeper and darker hues. When you add white to a colour, it is known as tinting and this process increases the colour’s reflectivity. Shading is the process of adding black to a colour, which in contrast, will make the surface less reflective.
A white surface will always look red if it’s bathed in red light and this is because white contains all the colours. However, if you were to shine a blue light on a red object, the colour then appears much darker. This occurs because red doesn’t contain any blue, therefore it absorbs all the blue instead of reflecting it. So, the colour of a surface or object depends greatly on the type of light that is shone on it. The only true way to gauge the colour of something is to place it in a white light or natural sunlight.
Dark colours absorb more heat than lighter coloured ones. They heat up quicker in the sun and the reason for this is that dark colours absorb a lot more of the different wavelengths of light energy, whereas white or light objects reflect all of the wavelengths.