I spent some time wandering around with a light meter and have some observations from 62 year old eyes, glasses of course.
10 - 20fc. Typical light found on the interior of many job sites. Not enough, but often made to work. Not good.
40 - 55fc. Adequate light, I read highly detailed drawings in this
light all the time.? Probably the minimum you'll want in a shop
environment.
70 - 85fc. A very good amount of light on a machine, work bench, etc
.
200 - 500fc. The light directly under a bright task light. I have two
"Uberlights" (http://tinyurl.com/znj5n9m) in my shop and one in the
mockup room in my office for when I need to see fine detail or work on
tiny things, they are wonderful. Make sure to get the LED, there is a
Halogen $10 less.
The absolute best lighting, in my opinion, would be to light the
entire shop to 40 or 50fc, then kick the levels up to about 80fc at the
benches and at the machines that need it, plus a machine lamp like the
Uberlight at milling machines and similar. Cheap track lighting with LED
narrow floods would work great, very adjustable if you move the
machines.
This is for a windowless area. If there are a lot of big windows with
no tinting you'll probably need a lot more light, your eyes close down
when they track across a bright window and that makes everything in the
space look darker. I often film large view windows back 50 to 80% and
the effect is to make the room feel much brighter as your eyes will
accept more of the interior light.
Brian(J)
