I'll be your street light, baby... and I'm lighting up your town... Army cadences still get stuck like old songs.
This is a night time photo from when I hung my lights. The main bay shown is perfect. I did add additional light, 2 high bays wasn't enough on their own in the partitioned space (follows same grid and spacing as shown), so I bought 3 more. I'm going to add one each above the operator's position on the lathe and mill, and I might use the third one over my welding are near the man door.
I'm just over 250 lumens per square foot (lux) here, or 25 foot-candles, depending on your reference material. I benefit from additional task lighting sometimes at the bench, and I certainly use machine lights. Someone's gotta pay the bill, so I don't have a tanning salon running in my shop, and I'm already twice as bright as a fine-item warehouse. If I need clean room lighting, I'll use a bench light, but otherwise, I'm really happy with the light output I have.
For demanding visual tasks, use the IESNA Illumination Guide:
Public spaces 30 lux
Simple orientation for short visits 50 lux
Working spaces where simple visual tasks are performed 100 lux
Performance of visual tasks of high contrast or large size 300 lux
Performance of visual tasks of high contrast and small size, or visual tasks of low contrast and high size 500 lux
Performance of visual tasks of low contrast and small size 1000 lux
This breaks down into more refined recommendations:
Warehouse (active, bulky items, large labels) 50 lux
Warehouse (active, small items, small labels) 100 lux
Simple inspection or assembly 300 lux
Difficult inspection or assembly 500 lux
Exacting inspection or assembly 1000 lux
Welding-orientation 300 lux
Welding precision manual 1000 lux
Rough bench or machine work, 300 lux
Medium machine work (automatic) 500 lux
Fine machine work (manual, grinding) 1000 lux