Wednesday 9 February 2011

Learning about green screen

Today, I went into uni and learnt about setting up green screen, particularly lighting the studio and also using tracking markers to measure the speed/distance of camera movements.  I helped in setting up the lighting and I also attaches tracking markers to the green screen.  The tracking markers are the white bits of tape stuck on the screen pictured below, 1 metre apart from one another, both horizontal and vertical.
The advantage of tracking markers is that if there is intended to be any camera movement in the piece, the rotation and speed of the movement can be judged by how the points move across the screen, and this movement can be matched in the movement in the CGI shot.

Unfortunately, we do not yet have hold of our parkour runner and we only have two days to film in the TV Studio as there is such huge security.  The good news is, however, that there is an alternative piece of technology called Chromaflex.  This is portable and can rented from our College shop.
Chromaflex involves a sheet of material, which I believe is made from tiny bits of glass.  This piece of material is illuminated with a green light that is attached to the camera, effectively turns the screen green, when filming.  This may be an option we will use when filming the shot where our parkour runner runs into a dead end.

Another option for getting hold of green screen capabilities is to purchase our own material.  Our tutor, Gareth recommended a shop in Soho called Borovick's where we can purchase green chroma material.  This all depends on how important the green screen sequences will be in our piece, but this will depend on how the storyboarding turns out.

We did some tests using green screen in the TV Studio, that consisted on me running in the same manner as our main character, along with some close up shots of action figures to see how the final shots of our piece may look.  Those are on the computers of the other team members so check out the other blogs if you want to see them.

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