Accessory pigments are xanthophyll, chlorophyll b, and carotenoids, also known as photosynthetic pigments. They help in accumulating solar energy and passing them to chlorophyll-a. They are not directly concerned with the emission of excited electrons. While doing so, this pigment absorbs maximum radiation in regions – blue and green. As a result, chlorophyll-a is the main pigment, and all other pigments, such as carotenoid, chlorophyll b, and xanthophyll, are accessory pigments.