I have found the following link to have an EXCELLENT portion on indoor lighting of orchids -
http://www.orchidsusa.com/3Lightlevels.htm.
For starters, I found the measured light intensity in September, at noon, from a large south window interesting -
6000 fc by the window
4000 fc against the screened pane
3000 fc 1 foot away (in sunlight)
600 fc 2 feet away (in shade)
500 fc 3 feet away (in shade)
400 fc 4 feet away (in shade)
<200 fc 10 feet away under a skylight!
Note especially his comments about growing under fluorescent and high intensity lamps!
I also have a fairly good book by Charles Marden Fitch termed "Growing Orchids Under Lights" which promotes either HID lighting or special horticultural fluorescent fixtures that hold EIGHT tubes in about a 16" width. Even with this many bulbs crammed into a small space the plants are just inches from the fixture (which is not necessary with HID lighting that has its own challenges).
What I "THINK" I have learned from all this is that only my phals and paphs will do well with my shop light fluorescent setup and my other medium and high light need orchids need to be outside as much as possible to promote blooming during the nice weather portion of the season. After a year and a half this is indeed what seems to be the case.
Anyway - possibly this will promote some more discussion and you all can help me gain additional understanding about how all this works! mike