A few notes from San Diego Premiere Pro Meeting 27 February 2019 and more.
Setting Up the Green Screen for Filming
- Place subject 6-7′ away from the green screen. This minimizes shadows falling on the screen.
- Keep green screen as flat/smooth as possible.Light green screen evenly (2 lights, same temperature are ideal). Check with a Light Meter or Phone App.
- Lux Light Meter (Google Play) *
- Light Meter (Google Play, free) *
- Smart Luxmeter (Google Play) *
* This is in no wan an endorsement, only a place to start research.
- Light subject so they are 1-1.5 stops brighter then the green screen.
- Knowing what the composited background will be will allow you to setup the lights and light the subject in a more convincing way.
- If possible adjust depth of field to keep the screen a little out of focus.
- Higher shutter speeds can help with motion blur
- Use uncompressed formats for heavy keying (422 recommended)
- Log is rarely useful because you have to color correct in order to key
- DSLR: flat as possible, ISO increments of 160
Green Screen Tips – Software
Ultra Key: Premiere Pro Plug-in
Start with a garbage matte then use Ultra Key to remove the green around the subject. There are different output settings (Composite, Alpha Channel – all keyed areas are black, and Color Channel) to check the results. Settings give a preset depending on how good a green screen you are starting with. Start with the eyedropper to select the color to key out (it doesn’t have to be green).
- Green screen tip: use a Curves Adjustment before Ultra to get a better green.
Primatte Keyer by Red Giant
Primatte is a plug-in for Premiere Pro, After Effects, Final Cut X, and Apple Motion. It allows you to select your background and foreground, and to separate them out for a great key. Primatte/Red Giant
Keylight: After Effects Plug-In
The drop down menu gives several options including: final result, source alpha (transparent parts shown in black), outside mask, inside mask, status, and more. The inside mask can help if there are parts on the inside of the subject that are being keyed out. Status can help show problems. Despill Bias can help with soft wispy hair. Under Screen Matte, Clip Rollback can also help with hair. For more information Adobe has a page on Keying in After Effects.
Books on Green Screen
- The Green Screen Handbook by Jeff Foster
- Green Screen Made Easy by Jeremy Hanke, Michele Yamazaki Tepstra