What type of material should I look for in a filter?

That decision is based on your application, each type of material has its own pros and cons. We supply three major types of materials used for our filters: glass, optical cast plastic, and gelatin film. Glass filters are the most durable and generally have the best surface accuracy, but can be expensive and weight becomes a factor in an assembly. Optical cast plastic filters are lightweight and have excellent thermal and chemical resistance, but tend not to have as precise a surface accuracy and are also capable of less transmission than a glass filter. Gelatin Film filters are extremely lightweight, very thin (on the order of 0.1mm) and can be cut by ordinary scissors into any size or shape. However, they have less transmission than glass or plastic filters, need to be handled only by their edges, need care in mounting to ensure a flat surface, and can only be stored in temperatures below 50°C.