Naturally, the closer to the 555nm green peak, and the more monochromatic your light source, the brighter it appears to be. This is a part of why night vision systems are green.
You measure a lumen by taking the area of your light source spectrogram in respect to the luminosity function.
I did this years ago with some manufacturers LED light output curves to reverse engineer electrical->photon efficiency vs cost from their data sheets. The main purpose was to figure out how close we were to LED lighting taking over.
I did that research back in 2012 and predicted 2015 as the point where LED was more efficient and cheaper than CFL but I was off by a year or so. Hilariously that paper got me a C- because it was only tangentially related to the teacher's pet subject and never saw the light of day.
Naturally, the closer to the 555nm green peak, and the more monochromatic your light source, the brighter it appears to be. This is a part of why night vision systems are green.
You measure a lumen by taking the area of your light source spectrogram in respect to the luminosity function.
I did this years ago with some manufacturers LED light output curves to reverse engineer electrical->photon efficiency vs cost from their data sheets. The main purpose was to figure out how close we were to LED lighting taking over.
I did that research back in 2012 and predicted 2015 as the point where LED was more efficient and cheaper than CFL but I was off by a year or so. Hilariously that paper got me a C- because it was only tangentially related to the teacher's pet subject and never saw the light of day.