[Radiance-general] coloured glass.........

[George Michaelson]

in my experience (lived in York for 5-7 years, a *lot* of stained glass there
in the minster) stained glass is grey-black with a lowish reflectance on the
outside: dirt mostly. -The leading is generally visible but also has a very
low reflectance. being able to see a tracery but not really see 'through' would
be normal.

couldn't that be modelled by two one-way transparent/translucent substances
one inward facing, one outward, the outward one with a texture?

nighttime is different. I think thats the real problem.

(a lot of stained glass is also now covered with anti-pigeon mesh. Glass in
 York minster is a 3-layer sandwich, to protect the medieval panes from 
 exposure and other damage and the like. thats also reducing its transmittance
 I expect)