The proper term for ambient light is ‘illuminance’, the received light that falls on a surface, which we measure in lux. 

Get into the habit of using a meter to measure critical positions in workspaces as it really helps you read a space and understand the huge variations that our eyes can’t pick up (as human perception of light is logarithmic). 

And carrying one makes you look like you know what you’re doing!

I have an Excel worksheet I use for teaching that walks you through all the main measurements, recording them, plus useful calculators. Message or email me and I’ll email you a copy.