Lee resin filters are made from lightweight polymeric materials which makes them easy to handle and wipe clean every filter is individually hand made by skilled technicians and is the passed through a rigorous quality control system to ensure 100 accuracy and consistency the real blue filter adds realistic colour to flat skies and is available in three strengths 1 being the most subtle to 3 being the strongest graduated filters feature an area of colour at one end of the resin with the op