On Mon, 30 Aug 2004 06:53:44 -0700, "starlord"
wrote:

I have no idea what you are talking about, transmisson grating? I know of no
such thing.

A transmission diffraction grating is the same as a reflection grating
but it's cut in clear material instead of into aluminum. They used
to sell them as special effects filters for cameras that produced
a spread out spectrum of bright objects.