Photosynthetically Active Radiation (PAR) vs Human Eye Sensitivity Spectrum #2173130 (License: Personal Use)

This infographic compares the human eye’s spectral sensitivity curve with the photosynthetically active radiation (PAR) range (400-700 nm), overlaid on the full solar spectrum from ultraviolet (400 nm) to far-red (700+ nm). The shaded SL (solar light) region indicates total irradiance, while PAR shows the biologically relevant band for chlorophyll absorption; a young seedling illustrates real-world plant response. Labels for wavelength (nm), intensity, and key zones clarify how light quality affects growth and vision.

Used in horticulture, agronomy, and lighting design resources to explain why full-spectrum or LED grow lights prioritize PAR over human-centric lumens; targets growers, educators, and researchers seeking science-backed lighting strategies.