- Light the green or blue chromo screen backdrop and the foreground talent separately.
- Before you begin lighting a green or blue chromo screen sequence, you need to know exactly what the backdrop will become. If possible, have an editing system on set so that you can simulate your composites, so that you are able to see if your foreground lighting fits in with the backdrop image that will replace the chromo background.
- Make sure the shadows of the key light fall in the same direction as the backdrop, and that the quality of the lighting, color temperature and the angle of the lighting are in harmony. If your chromo will eventually be replaced with a muted soft landscape, your foreground subject needs soft lighting. If your backdrop will become a harsh desert, you foreground subjects need hard lighting. There is no bigger give away that the backdrop was fake, then if your foreground subject shadows and background subject shadows are moving in polar opposite directions to each other.
- Green or blue chromo screens are not exactly conducive to motivating actor imagination that they are on an exotic location, so do try show talent the intended backdrop image, so that their performance is motivated to the intended location.
- Use a green or blue chromo screen location with the largest backdrop surface your budget allows. I understand you may not have the “Iron Man” green screen budget, but remember that small chromo screens equal big problems, as small chromo screen restrict lensing options, ie how wide you can shot before your talent is not juxtaposed against a chromo backdrop, and as a result you end up shooting off your set.
- The green or blue chromo backdrop should be lit with a shadow-less, even as possible quality.
- Do not over light the green or blue screen. The more light you have on the chromo, the more chance you have for the green or blue color of the backdrop reflecting spill light onto the actors, thus compromising a clean composite.
- It is preferable to underexpose your green screen up to one stop darker to avoid green spill light. With blue screen you have to be carefull as underexposed blue goes black. So rule of thumb for me is green screen 1 stop under the camera exposure, blue screen at camera exposure.
- Keep the talent as far away from the green or blue screen backdrop as possible, this again will help ensure that you have the least amount of unnecessary chromo spill light seeping onto the reflection angles of the talents faces or bodies.
- I either use space lights or tungsten nine lights through 1/4 grid cloth to light green screens evenly.
- I primarily use four -point lighting approach for the foreground talent for chroma screen work, key light, fill light, and two back light cross keys to ensure the cleanest composites and separation from the chroma screen. I position the cross key back lights at 45% angle from both sides. I keep the backlights anywhere from a 1/2 a stop under exposure to a 1/2 a stop over exposure.
- Another great trick is to use 1/8 magenta gels on your backlight for green screen and 1/8 yellow gel for blue screens, as these are the respective complementary colors of the potential chroma color spill.
- Another good reason to keep talent as far away from the chromo screen backdrop as possible, is to avoid the talent casting shadows on the chromo screen.
- If you have to paint your chroma color on the floor, keep it as spotless as possible by not having crew walking on the floor unnecessarily, or if they have to, provide surgical socks for crew to walk in.
- Is green or blue better for composites? Because green has a brighter color channel then blue, and blue when underexposed tends to have more noise then green, green is the color of my chose if possible for green/blue screen work. That being said, blonde hair is easier to key against blue screen backdrops. However, with today’s software composite packages, either green or blue will do the job. Therefore, a second important criteria to consider in your decision is wardrobe. If you are dealing with primarily blue wardrobe the of course a green screen backdrop makes more sense and visa versa.
- If you’re shooting in a 16:9 aspect ratio, you could set the camera to a 4:3 aspect ratio for chromo screen work, unless your framing something that will fill the entire frame horizontally. This will ensure you have the most resolution possible. Also feel free to crop in a little tighter then the final frame will be, as you will always benefit in resolution if you gather more information and are able to reduce the size in the composite.
- Another trick to squeeze the maximum amount of resolution into your cameras gathering of information process, is to tilt the camera 90 degrees for shots of standing people, thus utilizing a lot more horizontal information into your subject, that you will later be able to reduce in size in the composite.
- Color temperature i.e. shooting green screen with Tungsten or HMI is not a huge consideration. Again what is of most important is to treat the background and subject separately.
- Do not forget to add some effects and texture to sell the trick. If the background is garden, have for example a cucalorous which is organic wooden shaped cut-out in front of your key light source, to simulate the effect of the sun moving through branches and leaves.
- A good green paint for excellent composites is Rosco’s Ultimate Chroma Key, but today’s software is so sophisticated you will be able to extract good composites with almost any chromo paint.
- Ensure that you do not have reflective and shiny props like jewelry or earrings when you doing chromo screen work, or you will need to become a rotoscope export in post.
· With compositing, shoot progressive [frames] rather than interlaced [fields] to get the cleanest edge and highest resolution.Weather you go green or blue, I trust these tips will get you though your chromo day very successfully. If you have further questions please don’t hesitate to contact me personally through my site at www.daronkeet.com
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