<page_title> Luminous efficacy </page_title> <section_title> Photopic vision </section_title> <table> <cell> Ideal monochromatic 555 nm source <col_header> Type </col_header> </cell> <cell> 683 <col_header> Luminous efficacy of radiation (lm/W) </col_header> </cell> </table>
The photopic luminous efficacy of radiation has a maximum value of 683 lm/W in the case of monochromatic at 555 nm.