The base material is a special 12-micron, tear-resistant foil with excellent optical characteristics, a spin-off from space and nuclear research high density ripstop films. It features a double layer of vapor-deposited aluminum these superimposed layers of metal provide an optimum uniformity of the filtering layer. The thickness of the aluminum layer is continuously verified by opto-electronic means.
The metal layer reflects 99.999 % of incident light and transmits only 0.001 % (one hundred-thousandth), corresponding to welder’s glasses of optical depth 13, according to current medical knowledge, filtering action at this order reliably rules out any possible thermal damage to the retina (thermocoagulation). The film can be used on cameras or telescopes.