Light through Stained Glass

futerfas · October 6, 2004

I have a shoot coming up where the director wants a shaft of light coming through stained glass in a church, and I know this can pose many difficulties. I've seen DPs try and fail to achieve this effect, having worked as an electric for a long time. Has anyone had a lot of success with this?

Obviously, I need a smoke machine for the interior to show off the shaft, and I'll probably need a big light (12K PARs and Xenons come to mind). I'm wondering if I can achieve the desired result with a 4K or 2 (we don't have a huge budget), or maybe even figure out when the sun will be in the right place (sunPATH) for the shot. I don't want to melt the glass or the typical lead lining of the glass. I also have seen stained glass that is too thick to penetrate.

I haven't yet seen the location, which will answer some questions. Any thoughts? What has worked for you?

-Graham Futerfas

Alvin Pingol · October 7, 2004

If you must settle for smaller lights, place them closer than normal to the stained glass. However, this will result in the shafts of lights spreading "outwards" from the window, versus a straight shaft, which you may want.

A 2k might work, so long as it is very focused and very bright. To avoid melting the glass, simply keep the lights off until rolling begins, and turn them off again when cut is yelled. Unless your scenes are really lengthy, you should be fine.

Riku Naskali · October 7, 2004

Obviously, I need a smoke machine for the interior to show off the shaft, and I'll probably need a big light (12K PARs and Xenons come to mind).

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Use water based cracker / hazemaker, regular smoke machine doesn't really cut it.

futerfas · October 7, 2004

Why the water based? I usually get the F-100 for something big like a church. -- They're fire-breathing dragons if you want them to be. Is that water based?

I'm no smoke machine expert, but I've had some that don't work at all and others that can make it so thick you can't find your way to craft service. The F-100 is typically used in big arenas, from what I understand. I don't think we'll have a Special FX dept. on this job -- which means it will be a PA pushing the button and bugging me about the "smoke level" every 3 minutes.

-Graham

Michael Nash · October 7, 2004

There was a whole thread a while back about smoke machines. The DF-50 is the standard haze maker these days.

A 2K won't give you the power to punch through stained glass, and even in full spot it will spread too much to give you distinct shaft of light. Putting the unit closer to the glass for more brightness will make the beam spread even more, and won't cover the full area of the window.

This is one of those things where if you really want it to look like a shaft of light, you got to really provide a big, far away shaft of light! There's a reason people use things like xenons for this!

Personally I wouldn't attempt this with anything less than a 6K HMI, although a 4K could work if the window is small enough and you're shooting fast film at night, where ambient daylight isn't flooding the space and washing out the beam.

Using real sunlight works great IF the sun hits the window and projects a beam in the desired direction. It may slice straight down or be blocked by trees. If you get lucky enough to use real sunlight, save that precious moment for the big wide shot. Then you can fake the beam closer up with artifical units inside the church, and a fake "gelled glass" window (gel taped to plexiglass).

Michael Nash · October 7, 2004

Incidentally even something as small as a 2K can break double-paned glass if it's too close (stained glass windows are sometimes protected with a layer of clear glass). The airspace between the panes gets superheated and shatters the glass. It happened to a friend of mine.