Green screen best practices

A green screen can give you greater control over how your image appears in mmhmm. Learn how to use a green screen with mmhmm and enhance your image quality.

Green screen types and settings

You can use two types of green screens with mmhmm: virtual or physical. The virtual green screen is selected by default, but if you have a physical green screen, select I have a greenscreen in the Camera settings menu.

Virtual green screen
The virtual green screen is included with mmhmm and requires no additional setup. It automatically detects the position of your head and torso in the foreground and separates them from your background, allowing you to take advantage of mmhmm's rooms (or backgrounds). It's automatically activated when you choose the silhouette frame in mmhmm's presenter settings.
Physical green screen
Physical green screens are usually made of green fabric and hung from a stand or frame in your physical environment. Frequently used in film and TV recordings and online streaming, the bright green of these backdrops makes it easier to superimpose the subject in a virtual scene digitally. While these require more effort to acquire and set up, they are currently the best way to make the subject "pop" in a virtual room.

Green screen in-app setup

  1. In the bottom right of the mmhmm stage, click the Camera settings drop-down menu and select I have a greenscreen.
  2.  Click Auto-adjust to let mmhmm configure your green screen settings automatically.

    mmhmm green screen settings.png

To manually select your green screen color and threshold percentage:

  1. De-select the Auto-adjust feature.
  2. Select the green screen color under Color.
  3. Set the threshold percentage under Threshold to dictate the sensitivity of green screen detection so mmhmm recognizes the darker and lighter areas of your green screen. Adjust the range of hues that match your background using the threshold sliders. Experiment with the upper and lower bounds until you have a crisp silhouette.

Light your foreground

The existing lighting in your room should be sufficient for mmhmm, but lighting your face with other sources of light can further improve the quality of your image. 

Generally speaking, studio lighting concepts translate well to mmhmm:

  • Ideal studio lighting illuminates a subject with soft, diffuse lighting from multiple angles to eliminate hard shadows. 
  • In a typical three-point lighting setup, the main source of light (the key light) is set at an angle to one side of the subject. A second, softer light (the fill light) is used on the other side of the subject to fill in the shadow caused by the key light. The larger the difference in light intensity between the key light and fill light, the greater the shadow. ThreePointLighitng.png
  • A third light is sometimes used to light the subject's hair and shoulders from behind. This enhances a subject's silhouette and can make them stand out from the backdrop or green screen even better.
  • Fabrics are placed over the lights to diffuse the light. By increasing the surface area of the light source, the light is "softened" which creates a more flattering lighting effect. To achieve this diffusion effect, studio lights are placed in softboxes or bounced off silver-coated umbrellas or through white, translucent umbrellas. 

SoftboxUmbrella.jpg

Even without professional studio equipment, these concepts can be used to combine the natural and artificial lighting in your environment to replicate these effects. For example, a desk lamp bounced off the cover of a book can be used to greatly enhance the lighting quality of your image. 

For more lighting tips and types of lighting to improve your video, watch the following video.


If you're looking for a light, consider the Elgato Key Light Air.

Fix green outline when using a physical green screen

This green outline is called a green screen spill and can be reduced with the following steps:

  • Shine more light on yourself instead of on the green screen behind you.
  • Adjust the green screen threshold while working with your lighting.
  • Crop your image.

Don’t see the answer to your question? If you’re having technical difficulties or want to suggest a topic for this guide, submit a support ticket or email us at help@mmhmm.app.

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