Plants absorb specific wavelengths which promotes these areas of their development:
200nm-280nm UVC ultraviolet range tends to be extremely harmful to plants.
280nm-315nm UVB, an intermediate ultraviolet wavelength is harmful and will causes plants colors to fade.
315nm-380nm UVA, the wavelength that causes tanning in humans is neither harmful nor beneficial to plant growth.
380nm-400nm The sorter wavelength of the visible light spectrum. Process of chlorophyll absorption begins.
400nm-520nm This is a very plant usable range of the violet, blue, and green bands. Peak absorption of chlorophyll occurs via photosynthesis, and and is the main promoter of vegetative growth.
520nm-610nm Is mainly a dead range (green, yellow, and orange) because it has less absorption by pigments.
610nm-720nm This red wavelength is the main absorption by chlorophyll, and most significant promoter of flowering/budding.
720nm-1000nm Absorption by chlorophyll is generated very little; flowering and germination, however is influenced. The low end of this frequency is unwanted heat, IR.
1000nm and below is IR and is nothing but unwanted heat.
Full Spectrum LED's use 70% Red, 20% Blue, 10% other spectrum colors which cover 380nm-840nm. Research has shown the best results with this coverage over years of trial and error. We personally tested and find these results very much promote the vegetation and flower stage of cannabis.
We also incorporate warm white (found to be very useful in flowering) and soft white (useful for vegging).
Red light is important to plant reproduction. Photochromy pigments absorb the red and deep red portions of the light spectrum and regulate seed germination, root development, tuber and bulb formation, dormancy, flowering and fruit production.
Royal blue light stimulates Chlorophyll production more than any other wavelength and encouraging thick leaves, strong stems and robust vegetative growth.