How necesary is heat dispersing / dissipating glass? I bought a second hand Durst Lab G139 that came without the HD glass for the filter tray. Somebody suggested that as the Ilford multigrade filters are acetate they won't melt. Considering the filters will be about 5cm (2 inches) from the uncooled 300W bulb I am not going to test this until I get a second opinion. Does anyone run this type of setup without the HD glass? If the glass is necesary, any idea where I can get some (very cheaply) in Australia as nobody seems to have heard of it?