Essential Tips: Shooting Green Screen for Chroma Key
Shooting video on blue or green screen can be tricky. Follow these tips for success and pull the cleanest key possible!
Image from HyperXP on Flickr
When done professionally, green screen can provide an excellent way to achieve unique effects in your video projects. When shot incorrectly it will be the very bane of your existence (especially if you’re the editor!)
To start, let’s shed some light on this debate: Should I use a green screen or blue screen for my chroma keying?
Today, green screen is the most common color for chroma keying. The sensors of video cameras are most sensitive to green, so green will most often produce the cleanest key. This is due to the fact that “the green channel has the highest luminance of all three (red, green and blue) digital channels, and thus the sensors deliver the least noise in that channel” (from AWN.com). It’s also worth noting that “green is the color that is furthest away from human flesh tones” (from Lightcraft).
There are some instances however, when a blue screen may be more appropriate. If you’re shooting someone with blonde hair, it is often easier to pull a key with a blue screen (green can spill into light colored hair). Of course, if you have any green elements in your shot, such as foliage, it may also be best to use blue to avoid keying issues.
In the large majority of cases, chroma keying with green screen is preferential over blue screen.
Image from Bob Bekian on Flickr
From lighting and shot setup to keying in post, we’ve rounded up some of the best tips for shooting green or blue screen video….
FreshDV’s Top Tips for Better Green Screen
Although this post is a few years old, it’s certainly worth sharing. Their 10 green screen tips is a quick rundown of all the main points to consider when you’re doing a green screen shoot. Two from the list that may not be all that obvious:
1. Keep It Blurry
Turn off all in-camera sharpening and skin detail settings. Seperate the talent from the screen and strive for a shallow DOF. Seperation also helps control light spill.
6. Proper Props
Ensure that shiny props don’t reflect the color of your screens. Or don’t use shiny props.
Head over to FreshDV to check out all 10 chroma key tips. It’s a good list that shooters should share with their producers, and vice versa.
FilmRiot’s “How to Green Screen” Tutorial
The always entertaining Film Riot crew demonstrates their workflow for shooting for chroma key. In this video they give a general overview of shooting on green screen, as well as how to pull out your chroma key in post production.
In this video they give their own top 10 tips for a better green screen. Jump to about 3:30 to get into the tips:
Digital Anarchy’s Lighting for Chroma Key
As the saying goes, the devil is in the details. When it comes to chroma key and green screen, those details most definitely have to do with the lighting.
It will be next to impossible to pull a key from a poorly lit green screen shot. Digital Anarchy has an entire post dedicated to the subject of lighting for green screen. I’d highly recommend taking a look at the whole post, but here are the three main takeaways you should know:
- Make sure the chromakey screen is lit evenly across. No hot spots or shadows.
- Be careful that your model does not cast shadows on the chromakey screen. She should be 6 to 10 feet in front of the screen and lit separately.
- Set up two lights, one from each side, and both a good distance from the screen. This will avoid getting a bright ‘hot’ spot in the center of the lit area.
Image from fliegender on Flickr
Got green screen and chroma key tips to share?
Share your thoughts and suggestions in the comments below?