What are chloroplast pigments?

Chloroplast pigments are colored substances that absorb energy from certain wavelengths (colors) of light.
The most abundant pigments are chlorophyll a and chlorophyll b.
Chlorophyll a absorbs mostly violet-blue and orange-red light whereas chlorophyll b absorbs mostly blue and yellow light.
Other pigments are carotene, which absorbs blue light and xanthophyll, which absorbs blue-green light.
The pigments are placed together in an antenna complex to maximise absorption of light. The light energy they absorb are converted into excitation energy which is passed to the reaction centre.

Action Spectrum

The action spectrum is a graph that shows the rate of photosynthesis at different wavelengths of light.
The action spectrum reflects the combined activity of all photosynthetic pigments. At any particular wavelength, the photosynthesis is carried out using the light energy absorbed by all types of pigments together.
Different plants have different action spectra depending on their composition of chlorophyll a and b, carotene and xanthophyll.

The absorption spectrum is a graph that illustrates how much of each wavelength of light a particular pigment absorbs
The peak absorption of each pigment is the wavelength at which it has the highest absorption.
As different pigments peak at different wavelengths of light, the plant can utilise the full range of sunlight wavelengths.