What is thin film?
There are many thin films on the market today used for solar viewing. Some of them include Mylar, Baader, Black Polymer, etc. The thin film that we use for our filters is a black plastic polymer. It has a neutral density (ND) of 5 and therefore is safe for solar viewing. The sun is viewed as a sharp natural orange image, not blue or white. It is less expensive than coated glass filters.