BS 679:1959

Classifies filters into shades according to visual density, recommends shades for various industrial uses. Visual density, protection against ultra-violet radiation, total-heat protection, antiglare protection, refractive properties, freedom from optical imperfections, uniformity of density, permanence, quality of cover glasses, colour grading, and (for plastics filters) flammability tests.

All current amendments available at time of purchase are included with the purchase of this document.