Green!!

[Gareth56]

I'm lead to understand that green is the easiest colour to replace when working in a digital format hence green screens etc in films, why is this?

Edited April 7, 2009 by Gareth56

[swansont]

They use green screens and blue screens. I imagine it depends on the color of things in the picture.

 

The differences between them are going to depend on how well you can resolve color difference. There seem to be special considerations depending on the medium.

 

On film, the green layer has the finest grain structure. On NTSC video, the green channel has the highest sampling rate.

 

The blue layer of film is sharpest but is also the grainiest layer. In video, it is the noisiest channel. If you are shooting DV Video (4:1:1), it is probably best to stick with green screen.

 

http://www.vce.com/bluescreen.html

 

 

I'm not sure what issues there might be with digital — apparently green has a greater bit depth than blue (at least in some formats) so it might make identification/substitution of green easier.

[YT2095]

blue and UV blocking filters are used in photography as a matter of course all the time, esp the UV blockers as these colors tend towards a haze effect on film, orange and yellow Pass filters are often used to make a scene look better.

[GDG]

Wikipedia has a pretty good entry on this.

 

Interestingly, some photocopies have this feature too (or at least, they used to). Try using a light blue pencil on text: when you photocopy it, the blue pencil should not show at all. Sometimes works with blue highlighters too.