Lighting ← Knowledge Base Where can I get a swatch Wide Rolls Are LEE Filters self adhesive? How do I attach my filters to some Perspex / window etc? How long will my Gel filters last? How thick are the gel filters? If I put my filters in front of an high watt lamp will they burn? How do I calculate colour temperature shift ( mired shift ) What are the lighting filters made from? What are the three primary colours? What does the Y value mean? What filter do I need to convert a xK lamp to a colour temperature of yK? What is the heat resistance of lighting filters? Where is my nearest Lighting Filter dealer? Will my filters burn? Your website refers to a Source C - what is Source C? B1 Certificate Lighting filters Achieving White Light / Additive / Subtractive mixing.