If getting more sleep was one of your New Years resolutions, I hear you. We bought blackout liners for the girls room about five months ago because we needed a solution for the bright light that kept interrupting the girls sleep (in other words-ours). Since we had linen curtains from our Indiana house, I wanted to see if I could make them work by just adding a liner. After reading all the mixed reviews, we bought these liners and have not looked back. The room gets exceptionally dark and I am happy that I get to continue using our linen curtains.
If you look closely you can see one of the many silver hooks we used to pin the liner to the curtains.
Here you get an idea of how opaque these things are.