Pigments are substances capable of absorbing light at certain wavelengths. This means that various pigments can absorb light of various colours. So, if pigment A can become excited by colour X, colour Y will stimulate pigment B. Once the pigment gets excited after light is absorbed, it provides energy for the future photosynthesis so that light energy can be used.

The most abundant pigment in plants is chlorophyll a. This pigment demonstrates the optimal efficiency between blue and red-light wavelengths

Other pigments also show optimal efficiency between blue and red light, as shown in these charts. In this chart, it is clear that the photosynthesis is on the best level between the blue and rot wavelengths (displaying a rate of photosynthesis).This is mainly due to chlorophyll a. This is also due to the action of accessory pigments, however. This means that in the range of red and blue light the rate of photosynthesis is higher.