Re: room project..
You could always put that mosaic type window paper. It is like tinted paper but the colors are dark and the paper thing is thick and it blocks light. If you are too much on light then you can you the colorful one from inside and the regular tined one from out, I bet you light would dare to come in...
But instead of paining it blk you could just have painted it in white with regular paint wall paint. It will make your room look big and will block the light.