Yo Ho PUFF MONKEY,
I have looked into this a bit, and have found that a very soft green light will work well, where as the other parts of the light spectrum do not. Try to imagine going outdoors on a cloudy night, and the electrical is out all over town. The amount of available light would be just enough that you could do something without killing yourself in total dark.
Keep the amount of light down to a serious minumum, and as well keep to a schedual of no more than say three minutes. In other words try to manage getting done with whatever your going to do within those three minutes.
Good Luck
smoke in peace
KingKahuuna