What is the physics behind a blue-yellow polarizer such as the Singh-Ray Gold-N-Blue filter which photographers use to add yellow or blue highlights to polarized parts of a scene?
I am not very familiar with those particular filters and I couldn’t find any details on them. However, it sounds like you are halfway there and what you need is a second polarizer on the other side of the cellophane. When you rotate one of the polarizers, you will get a range of colors coming through the whole sandwich and it will work in either direction. Here is a little experiment from the Exploratorium that does something similar.
