What is the dominant pigmen..

What is the absorption spectrum of a chemical pigment? What is the dominant pigment of photosynthesis?

chlorophyll, the green color of the plants.

Chlorophyll absorbs light most strongly in the blue and red but poorly in the green portions of the electromagnetic spectrum, hence the green color of chlorophyll-containing tissues like plant leaves.

for the exact absorbtion spectrum see:

http://en.wikipedia.org/wiki/Chlorophyll

Chlorophyll is dominant