Step 1

Keying
when you take some pixels on the image
according to there chroma information or lumer information
and you make them invisible so that you can replace that information
with something else

the most comment use for keying is done with footage shoot on a green screen
especially used for the weather man who is shoot on a green screen then the weather map is then placed were the green screen pixels were.

When filming my footage i want to make sure that i lit the green screen well
as evenly lit as possible and if i am planning the track the background footage i will need to make sure that the white markers are visible within the footage.
Also it would help me later when it comes to keying if my green screen material is nice and pressed free from bumps and crushed parts.


want to place my green screen file into the project panel
either by importing or dragging it from the fie directly into the pane l

then create a composition with the file by dragging it into my composition area

I am now going to select the green screen pixels according to its chroma information. The reason green is used in keying is because green is one of the only colours that you shouldn't find in the human skin were as blue and red are common colours which are found in skin, so if one was to use these other colours selecting the background would be a murderous task.