Original hypothesis:
The new lighting system is inadequate without daylight, during open hours on the shortest days and at all times at night.
This has been more than adequately confirmed by our study; it is simply too dark without daylight, despite some 5,600 watts of very good and expensive lamps and fixtures. We suspect the original designer used references intended for lower-ceiling rooms when the lighting was designed; examining the rendering of the space after dark shows that most of the light ends up on the ceiling and walls.A simple way to resolve the problem might be to substitute 1,000 watt lamps for the current 400 watt lamps, and add controls which could switch the lamps invidually. Another approach, and the one suggested by the librarian who first told us about this problem, would be to add task lights; depending on usage that might be more energy-efficient and combining them might be best.
A word about the modelling techniques we used. The use of the computer modelling technique, though difficult, has enabled us to reach conclusions that would have been much less accessible in other ways. We hope that in the future such tools will become more accessible.