Date: Mon, 28 Jun 1999 21:49:45 +0100
From: morrisbc-AT-halcyon.com (Brian Morris)
Subject: Re: PUPT: Lighting shadow screens


Bill wrote
>I've recently built my first shadow screen - 30" x 48" of white vinyl shower
>curtain - but am having trouble lighting it well.  I bought a 36"
>fluorescent fixture (30 watts) as the book I'm using suggested, but find it
>creates a band of intense light on the bottom six inches of the screen then
>peters out about six inches from the top.  My assumption is that more watts
>will only increase my diffusion problem.  Looks like a I need another way to
>do this.
 Bill,
One of the many hats I wear is that I am a photographer. In creating
shadows  one needs to realize that a point source light will create the
shadows with the sharpest shadows, (light a tungsten light source) and a
diffused light source will create shadows with soft edges. Also, the closer
the figure creating the shadow is to the light source and further from the
screen, it will be a softer shadow. And the closer the object is to the
screen and further from the light, the sharper the image will be.  Diffused
lights also have a great light fall off over the small controlled area of
space as compared to a specular light source. Speed is also a factor here.
items closer to the screen will apprear to move slower than items further
away from the screen. For example. a translucent cloud can move rapidly
across the screen while a figure slowly moves across. How?  Put the fast
moving one closer to the light, and the slow one next to the screen. One
can you this to their advantage in projecting three demensional scenes on
the the screen. Objects close to the viewer will be sharper and objects
further away will be softer. Also note that shadows created with diffused
lights are harder although not impossible to control to a specific point. A
variety of lights can create a wonderful effect on screen. i.e., A high
flourecsent for the sky, and a point light source for items on the ground.
also, use parn doors on point light sources for exact control of light
spillage. Flourescents can also be controll this way but with less success.


Brian Morris
Zak & Company




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