How to remove a green screen background for free

Green screen backgrounds come out for free in Video by Zaweba. Put your new background on a lower track, the green screen shot above it, and apply the green screen keyer with spill removal; then use masks to clear away anything the keyer misses, such as the edges of the screen or a light stand. It all runs offline on your own PC.

The keyer does the heavy lifting. Masks and a bit of colour work make the result believable.

Laying out the tracks

Video tracks stack from V1 upward, and higher tracks sit in front. Put the background, whether a video, a still or a generated colour, on V1. Put the green screen footage on V2 directly above it. Anything you key out of V2 reveals V1 underneath.

Applying the keyer

Find Green screen in the Effects tab and add it to the V2 clip. The green disappears and the background shows through. Spill removal takes out the green tinge that bounces off a green screen onto hair, shoulders and the sides of a face, which is often what gives a cheap key away.

Look closely at the edges at full size. Hair is the hardest part; aim for the edges to look soft and natural rather than cut out with scissors. If the key eats into the subject, especially green or teal clothing, there's no setting that can tell clothing from screen, so change the shirt next time.

Other keyers sit beside it for other jobs: a luma key for keying by brightness (black or white backgrounds), a colour key for a screen of another colour, and alpha adjust for tidying the transparency once it exists.

Cleaning up with masks

Green screens rarely fill the whole frame. The edge of the cloth, a clamp, the floor or the dark corner of the room will survive the keyer. Rather than pushing the key harder, draw a mask round the subject to cut those away. Masks in Video by Zaweba can be a quick rectangle or ellipse, a polygon, a pen curve or freehand, with feather to soften the edge.

This is often called a garbage matte, and it makes the keyer's job far easier. If the subject moves around, keyframe the mask or use Track forward so it follows them.

Making it sit in the scene

A clean key still looks fake if the lighting doesn't match. Grade the foreground so its brightness, warmth and contrast match the background, using the colour correction controls or curves. Colour match can nudge the keyed clip towards the background as a starting point. A little blur on the background, using a blur effect, imitates a real camera's shallow focus and helps the subject sit in front rather than on top.

Tips for shooting your next one

Most green screen trouble starts on set. Light the screen evenly, without bright spots or shadows, and light the subject separately. Keep them a few steps away from the screen so less green spills onto them. Avoid green clothing and very shiny surfaces. Fine detail like flyaway hair keys better from sharp footage than from soft or heavily compressed footage, so record at the best quality the camera allows.

With a well-lit screen, the keyer and spill removal in Video by Zaweba get you most of the way in a few clicks, and masks finish the job.