How much Fluorescent shoplight wattage for green screen

G

GregJ

Active member
I've been researching a while about green screen lighting and using inexpensive Home Depot fluoros to light the screen. So today I bought two fixtures, 4 feet in length, 40 Watt, 2 bulbs each, electronic ballast. They were a really good deal.

But when I hung them from the ceiling above the green screen (10' wide) they really didn't seem to throw off much light at all.

As an experiment, I used my Tota light with a 500W halogen and it lit up nearly the whole screen uniformly.

So have I misread what one needs for fluorescent lights for lighting the screen? Or are there higher wattage bulbs I missed?

I wasn't able to test green screen footage because I dropped on of the tubes. Smashed into a million pieces and spend the next hour picking up every piece...
 
Really depends on your exposure levels and your camera. ie some cameras need more light than others and stopping down of course requires more light. The distance of the lights to the screen also will affect this. I can tell you that good exposure is at 50-60 IRE for a green screen. If you have a waveform monitor or a camera with the marker function like the HVX (at least I think it can do that... I use a waveform...). Using an HVX at 5.6 and a couple of 4 ft two bank shop lights I was able to light a very small 4x4 ft screen once. Worked great, but havent really done much green screening on anything larger.
 
Take a look here:

http://www.coollights.biz/wordpress/archives/43

One of my customers used 2 bulb shop lights to light his DIY screen but it will take more than 2 to cover a fairly large screen. Just remember, flos don't have so much throw. You're 40w flos with 2 bulbs are roughly the equivalent of 350w to 400w or so of tungsten behind diffusion. You said that you used a Tota (500w?) and 500w worklight for about 1000w total? So you will still need some more fluorescent fixtures to get the same kind of coverage.
 
Thanks Jeff and Richard. Yeah, I think I need a few more fixtures to light the whole thing adequately.
 
I did this before, but used 4, 8 or 10 foot fixtures with two bulbs each. I made square with them and went around an 8'x8' green screen. Worked OK.
 
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