When we look at a rainbow we see the different colours because small particle of water in the air effectively split light into its component wavelengths. However, the rainbow is one of the very few examples where we typically see wavelengths of light on their own. The light that comes from the sun, for example, consists of all the wavelengths in the visible spectrum (and many others besides). Other sources of light (such as a naked flame or a man-made fluorescent tube) also emit most of the wavelengths in the visible spectrum. When we look at objects in the world we see them because they are illuminated by light (from the sun or some other source). Some of the light is reflected by the objects and detected by our eyes. This is why it is reasonable to say that without light there would be no colour. Objects that reflect almost all wavelengths that they receive tend to appear as white or near-white. Objects that reflect almost none of the wavelengths that they receive tend to appear as black or very dark. The reason that objects reflect only some of the wavelengths is mainly because they absorb certain wavelengths. It is colorants – also known as dyes and pigments – that absorb the light. Most dyes and pigments absorb all visible wavelengths to some extent; however, if they absorb some wavelengths much more than others then they appear coloured. For example, a dye that absorbs the shorter wavelengths (that normally appear blue in the rainbow) of the visible spectrum will appear yellow.