Ralph, as always, makes very valid and interesting points. Light does not bend about a corner....the relevance of the statement is that if you are working in a corner of your darkroom that is away from a small light leak around your door or window then it is entirely likely that the small amount of light coming several feet away from your dark area will not affect your materials. For example, close the door and stand where you are loading your film film into your developing tank, or placing your paper onto the easel of your enlarger. Take a sheet of white paper, and see if the light strikes the paper....you might be able to stand in front of the easel, or the developing tank in order to shield the objects that you want to "protect". As noted, curtains or caulking, or weather stripping will help....however, in some instances, the last bit of light that might "infiltrate" the darkroom might not affect your materials at all. No one would argue with the advisability of making the darkroom as light tight and dark as possible. However, there are instances wherein small amounts of infiltrating light will have little, if any, practical affect. To repeat, I am not advocating a cavalier approach in which light is allowed in to flow into one's workspace. However, I do believe that it is entirely possible to work in a darkroom that is not entirely Stygian.