Ok, this is probably a silly question, but here goes.

I've been leaving my new dog in my bedroom during the day so that she stays out of the contractor's way as they work on the house. Should I leave the light on, or turn it off? I can't decide if it's better to be dark, so that she can hopefully relax and nap, or if having the light is better to keep her in the normal day/night cycle.

I let her out at lunch, and the contractors have apparently been letting her out a bit during the afternoon, so it may not be as much of an issue as I think. But I am curious about the general thoughts on crating and lighting.

I got my dog a clapper for the sake of modern convenience. He has yet to use it but its always available if he needs it. For myself I got a sponge bob night lite with glitter paint. Primarily as preventive fathers feet to floor sleeping dogs accidents. Seems to be Primarily for me. I generally use my light more often then he uses his. :)

Surely even with the heaviest drapes, some light makes it in. Dogs can see much better in the dark than we can.

Froggy, don't worry about. It is probably better that the lights are off. As labman points out there is a certain amount of light coming in and dogs see quite well in the dark. Considering your dog is getting acclimated to your home, and you have workmen there, it is best to give her down time/comfort that the darkness brings.