Coloured Filter Glasses: An Intercomparison Of Glases Made By Different Manufacturers

Specifications of about 800 coloured glasses made by 13 manufacturers are examined and intercompared. The internal spectral transmittances of typical glasses are plotted in a series of 44 diagrams. A log (internal density) vs wavelength representation is used. Curves with similar characteristics are grouped together in the same diagram. The internal spectral transmittances for a number of different thicknesses of each glass type can be read directly from the diagram. The curves are identified in a table, which lists the equivalent thicknesses of glasses yielding approximately the same transmittance. Such information facilitates the choice of filter components of reasonable thickness.