He might have said, seek lux et veritas, light and truth, through adi alterum partem, pivoting to the other side. – that is, if Rabbi Hillel spoke Latin.
You can monitor the run time, the efficacy, the lumen output or the power consumption, and then we do real time measurements on the lux levels on the street level.
If you're going to get 1000 lux at your eye, it honestly doesn't matter if it's a warm source or a cool source, that's too high and you're already saturating your circadian system.
The history there is a little murky but the earliest known reason that we have comes from the lux fauna a series of Roman laws put in place during a drought in 162 BC.
When we use our phones were staring directly into a light source and how much light falls onto a certain area like our eyes, usually measured in lux is dramatically impacted by our closeness to the device.