Anthony Stillman wrote: > >...how much absorbance (is there) in BK7 crown glass 38 mm thick. > > Dominic, > > Transmission straight from the Schott data > <snip> > Sorry its not at 37mm thickness. I'll bet you can figure it out. Right, but you have to use Lambert's law.... log ti1 / log ti 2 = d1/d2 Dan