Why is blue light important in photosynthetic processes, and why is it not considered an absorbance?

Blue light is absorbed by carotenoids and is considered an absorbance.

Blue light is important for photosynthesis but is not considered an absorbance because it is a type of light, not a specific wavelength absorbed.

Blue light is absorbed by flavonoids and is considered an absorbance.

Blue light is absorbed by chlorophyll and is considered an absorbance.