Lighting Alchemy 02
Lighting for Green Screen & Puppets!
. (Operating a puppet is not as easy at is looks, I’ve got a new found respect for puppeteers.) When lighting green screen there are two challenges that need to be taken into account. The first challenge is lighting the green screen, and the second is lighting the talent. I’ll be tackling each of those challenges in this edition of Lighting Alchemy, so lets get to it...THE GREEN SCREEN
How ...
For this particular setup we were in Lyon Film’s studio which is roughly 25’ x 50’. The green screen is a foam backed chroma green material that was hung off of two stands and a cross bar which was positioned against the far wall. Two 150w HMI’s from Cool Lights were placed opposite from each other at a 45 degree angle to the screen. In front of each of these lights I placed a silk fairly close to the light.
Why ...
The first thing you want to do when lighting any green screen is to get the screen as far away from the talent as possible. This will minimize any green spill on the talent making for an easer time in post when you pull the key. To accomplish that, I made sure that we set the screen at the far end of the studio, making use of the entire length of the studio. Having lots of room to separately light the screen and then light the talent makes this process very easy.
The goal when lighting any green screen is to get a nice even illumination across the screen. To help me achieve this, first I chose two lights that were of equal wattage - two 150w HMI’s. This was done for two practical reasons: 1. They were the lights that I had available to me & 2. Of the two light sources that I was going to be using (Tungsten & Daylight) they were the closest to in color to green. (Blue is closer to green then orange on the color wheel.) Next I placed these lights at an even distance and angle from the screen. With this placement I got a pretty even spread across the screen. However, to ensure that I had an even exposure I placed diffusion in font of each light. I could have placed diffusion on the light itself- like 250 or 216. While that would soften the light it would still remain relatively "spotty". Using the frames of diffusion (in this case two silks) turned the spread of each source into a bigger area creating even illumination. When I metered the screen in both spot and incident there was no variation- even down to the 1/10 of a stop. If you find that you do have a variation of 1/10 of a stop, that is ok as that much of a difference will not hurt you.
Additional Tip ...
Here are two additional tips for getting a better green from your green screen:
1. Use kino lights with "true" green tubes. These tubes are specially designed for green screen work and will help to saturate the screen. And since they are a naturally soft source it is easy to get an even spread from them.
2. Use green filters to your lights. Depending on the wattage you are using this may or may not be a viable option. While the filters help increase the green output of the light, they do decrease the total light out put. The filters you need for this are: Lee 738 or Lee 138. (738 is better but it cuts the light output more then the 138.)
Here are a couple of shots of the setup & the puppets.
THE TALENT
How ...
Having relegated the daylight balanced lights to the green screen, this left me with a set of tungsten lights to use on the talent. For this setup I had a basic 3 point lighting kit that consisted of 2x 500w soft boxes and a 250w lowell pro-light. I also used a 42" photoflex white bounce flex fill as my fourth "light". While I did have four different lighting setups to get for this shoot, I kept the basic theory the same for each of them. The 250w pro-light acted as the rim light, a 500w soft box was the key, and the flex fill was my fill light. Placement for each of these was determined by the scene. Also, it should be noted that for one scene a puppet was watching TV. To help sell the effect I used the 250w pro-light with 1/2 CTB to act as my TV light. This light was pointed into the puppets face and then turned up and down to mimic the glow of a TV set. (I would have liked to use full CTB, but the light output of the 250w was not strong enough to read on the puppets face with the full CTB.) When settings the exposure and lighting the scenes I made sure that my talent was roughly 1 - 1.5 stops brighter then the green screen.
Why ...
The biggest consideration when lighting the talent against green screen is to determine what the background will look like. You need to know where the light will be coming from in the scene, and what the volume of light will looks like - is it day, is it night ... etc. For this shoot we did not have the specific background plates picked out before hand, but we did know what they were going to be and feel like. One location was a jail cell, another was a TV room / living room, and the final one was a kitchen. All of the scenes were to take place during the day and they would have a high key / comedic look to them. (Except for the jail cell which would be a little more stylized. The choice of high key lighting was also based off of genre considerations. Since it was a comedic shoot I wanted the lighting to be light and airy- reflective of the humor of the shoot. (Had it been lit dramatically and highly stylized the lighting would have been fighting the style of the piece and sending a mixed message. ) And using the tungsten lights helped to give the talent a warmer look to further reinforce the comedic feel that I was after.
Placement of the key and fill lights were determined by where the light source would be in the background plates. Since they were not picked out, and I wanted each location to look a little different I chose to set the key and fill on opposite sides for each scene. I chose to use the pro light as my rim light to give the puppets a hard edge of light around the puppet. This was done more as a technical consideration as it would help to separate the puppet from the green screen and remove any green spill from the puppet. For the TV scene the classic gag to sell the viewing of the TV is to flicker a light to simulate the glow of the TV, and I felt it was appropriate to use it here to help reinforce the final environment the puppet would be in.
Additional Tip ...
To further help remove any green spill there may be on the talent a minus green (magenta) filter can be placed on the rim light. This will help to cancel out any green that may be spilling on to the talent- especially if you do not have a lot of room to separate them from the green screen.
THE RESULTS
So what does the final result look like? I have provided a couple still frames below from the footage. (It should be noted that Jerry Turner did a great job at comp’ing together the final images from this shoot.) I’m happy with how it has all turned out. If you want to see more (and larger) pictures from the shoot check out my photos page. Hopefully the tips here will help you on your next green screen endeavor. Until next time ....
Cheers,
Ryan E. Walters, Cinematographer
