Skylight dormer window - reduce light
We have a 1960's Cape style home which was recently renovated, including the addition of two dormer windows to the upstairs. One is only open to the upstairs (attic space) and the other is a skylight dormer, open to the downstairs (kitchen).
At night, the kitchen is typically well lit. I dislike how the skylight dormer window is always lit up as well, since the other dormer window is never lit.
Can someone suggest a film or something to add to the inside of the skylight dormer window to reduce the light going out? I certainly do not want to reduce the light coming in (this part is lovely).
Thanks in advance.