I would suggest that if you have the room, a walk through light trap is the best alternative. Just remember light can only go round corners by reflection. Curtains are a bad Idea as they create dust and if you have wet hands they will soon be in a right state. Alternatively, I once encountered a darkroom with a single door that was fitted with a micro switch on the edge. It was wired so that when you opened the darkroom door it switched off the light in the room you were coming from, but turned it on again when you shut the darkroom door behind you.