Green screen dotty/grainy

Hello, I'm trying to make my green screen work perfectly.

I have a smooth green screen, but the chroma key shows black shades and dots.

How can I fix this?

I have tried some lighting.

I'm using a Wecam Logitech C170.


  • Triem23
    Triem23 Posts: 20,070 Ambassador

    Shooting greenscreen and how to fix it, literally, takes a book. Tough to tell what the issue is, but a big part of it is the camera you're using. Webcams aren't terribly high quality with poor color reproduction and highly compressed, jagged footage. 

    Is your lighting even? 

    There's a whole other range of possibilities that could be causing issues. Is it possible to upload a few seconds of your footage to test? 

  • aarondc
    aarondc Posts: 264

    Be great to see video footage of what you're experiencing?

  • Idrankwhat
    Idrankwhat Posts: 131

    The most common issues I have had with green screens are lighting and placement of the green screen itself.  You do not want to be so close that you are physically touching the screen you want to really be at least a foot away from the screen if at all possible this will reduce shadow and make a better keying experience.

    When you set your lighting you want the green screen itself lit up to reduce or eliminate shadows but not so lit up that it is washed out or has hot spots in the footage from the lighting.

    When you light yourself make sure that there is no shadows being cast onto the green screen where the camera will pick it up.

    Make sure you get as much of the wrinkles out of the cloth you are using as possible. Sometimes using a spray bottle with water and then either let it air dry or use a hair dryer on very low settings to remove wrinkles.  

    If you are doing the green screen on the cheap with green pieces of construction paper from an office supply store or walmart or somewhere you don't want to light the background to the point that there is any reflection, you will want to use a deflector for the light which could just be a white piece of paper or even a  styrofoam ceiling insert. If you have white walls or ceiling you can use the walls to reflect the light back on to both you and the green screen.  Just watch for shadows being cast and do what you can to eliminate from the  view of your camera.

    My guess is that your existing webcam is too old and not good enough of a camera to really do a proper job with the purpose you are using it for.

    I went and bought a new Logitech c920 webcam and set it to 720p for doing youtube videos and it seems to work well for that. I would use an external microphone though as webcam mic's suck.. the quality is very poor.
    The c920 has been on sale recently on both Amazon and bestbuy websites and in the store so check prices you can pick one up for around $60 USD the last time I checked. I spent $20 dollars more in the store at Bestbuy but still cheaper than full retail price and I got it instantly versus having to wait on the mail or UPS to deliver.

    Lighting is the most important thing outside of the quality of your camera.
    Don't stand too close to the screen. If you can turn around and touch it with your finger tips you are too close. Sometimes you don't have a choice but the further away you can stand or sit the better the key will be.

    Light both the screen and yourself independently if possible otherwise shadow's will be cast on to the green screen especially if you are moving around.

    Hope these tips help.