I'm not entirely certain that interview about the technology uses the right terminology? After thinking about it a while, I don't know that I believe a
prism is used to make a curved rainbow on the projection
screen... that would be an incredibly difficult thing to do... and the sort of thing you would
send out to an outside optics company, not manufacture in your prop shop with the same tools you use to cut acrylic, or the like...
Maybe we're just talking about a custom color
gobo, and he heard the
lighting designer say it's 'like a prismatic
gobo?' And then mis-spoke while bragging about the LD's work and called it a
prism?
I'm just thinking that light bends IN a
prism then travels in straight lines afterwards... if light curved... well... I'd be a lot more excited about lighting box sets.
Now, it probably is possible to take a long
prism and
bend it into a curve so what would be a straight row of
prism projection gets projected as a curved
line... but this would be incredibly difficult... again not the sort of thing you do by just heating up a bar of glass with your
torch and grabbing it with the vice grips... To get that perfect of a curve, with the prismatic
effect perfectly inline and not distorted by the curving process at any
point.... We're talking nasa sort of optical manipulation there... and even they sometimes have to go up and fix their optical mistakes.
I'm not saying it couldn't be done... but it seems like creating the rainbow you want with other means and then finding a bright way to project that color
image makes far more sense than trying to design a really high quality curved
prism and then figure out how to get enough light through it, to the right place, with no light leak.... I just think most theatrical designers would use one of the existing technology solutions that could do the same thing, probably better and with more certain results... but then.. the Met does NOT employ MOST theatrical designers....
Art Whaley
Art Whaley Design