Keylight after effects tutorial


Green screen removal is an essential skill to learn for every visual effects artist. Here we are with a series of Keylight after effects tutorial where we will be releasing Step by Step tutorial on the topic. The featured chroma key plugin for the week is Keylight for Aftereffects. We will start with basic Keylight after effects tutorial before advancing to more advanced chroma keying techniques. Later in the series we will look into green screen removal of badly shot green screen footage. So here is the first tutorial hope you will find it informative and useful.


After reading this article you will be able to successfully key out a simple green screen shot using Keylight plugin for after effects.

 Keylight after effects tutorial : Step 1

> Import your green screen footage inside after effects.

Keylight after effects tutorial : Step 2

> With the green screen footage selected click on effects button from the top menu bar. This will drop down a menu with various effects available. Select Keylight from the list. This will apply Keylight effect on to Green screen footage layer.

Keylight after effects tutorial : Step 3

Click on eye dropper tool next to Screen color (color you want to key out) button. Select bright green color from the screen, green color will be keyed out from the image by least affecting the foreground.



 Before selecting screen color



After selecting  screen color

Quick tip : Select the Screen color to key out only once. Further manipulation of the matte can be done using other parameters in Keylight. Selecting the Screen color more than once doesn’t sum up to previously selected color, instead it will result in undesirable removal of essential parts from your plate.

Work flow tip: Switching between Source and Status view modes facilitates decision selecting the right shade of Screen color.

Status view mode displays Black, White and Gray colors.


Status view mode indicating bad selection of screen color

Black stands for 100% transparency or in other word the background.

White stands for 0% transparency totally opaque in other words the character/object you want to keep (foreground).

Gray stands for semi transparent areas. Gray shades around the edges of foreground indicate a correct screen color selection and will result in a good key. If they are present in areas that you desire to keyout completely that is the Background zone, it indicates the need for better suited selection of Screen color.


Status view indicating correct selection of screen color

Keylight after effects tutorial: Step 4

> Optimizing the matte

After getting satisfied with Screen color selection by analyzing it in Status mode, switch to Screen matte view mode.


Screen matte view mode

 This will display a black and white matte created by Keylight based on selection of Screen color. Colors required to be keyed out should be total black whereas parts of the image desired to be preserved should be total white. Again grays indicate semi transparent areas and are good if present around edges.

Now is a good time to fix the matte and remove undesired grays in background or darker areas on foreground. Go to screen matte click on drop down symbol and select clip black and increase its value till you get pure black in the background. The clip black value should not increase 15. Now decrease the clip white value till you get pure white in the foreground with semi transparent grays on the edges. Do not decrease the clip white value below 85.


Clip Black and Clip White values changed


       Matte optimized by altering Clip black and  Clip white values

Quick tip: Clip black controls work more precisely than Screen gain similarly Clip white controls work more precisely then Screen balance. Priority should be given to clip black and clip white values against Screen gain and Screen balance controls. Later should be used only if required. Another important thing keep the changes in Clip black and white values to the minimum, as much as possible.

Keylight after effects tutorial: Step 5

Hit Ctrl+y to create a new solid select a bright red color. Place the solid beneath the green screen footage layer. Select the green screen footage layer Keylight effect and switch the view mode to final result.


You should see your green screen totally removed with foreground completely opaque with 0% transparency with edge detail preserved. In case of not getting results go back (step 4) and optimize the matte again to get favorable results.

Hope this article will improve your basic chroma keying skills using Keylight for after effects. Next time we will look into more advanced chroma keying techniques and tools in Keylight. Till than practice what you have learned. Happy chroma keying.