Institute of Contemporary Arts

Scratches and Sparkles

Date: 20 October 2006

I'm still nursing my mild obsession with Cerith Wyn Evans' take my eyes and through them see you', the title work in the show, which is a large, mirror-based projector in the upper gallery running a continuous loop of fully-exposed film. The film is slowly picking up dust and scratches, and on my way in and out of the building I keep checking back to see how the work's progressing.

Though the work has its echoes in rather more recent experimental film history, I've been hoping that an automatic Len Lye will appear: a field of scratches and sparkles something like Free Radicals, or Particles in Space. Unfortunately, in a tribute to the smooth running of modern projectors, it's not picking up quite enough dust and scratches to make very interesting viewing. Nevertheless, it's still a good excuse to hang out with the invigilators for a little while.

Most of the scratches are green, and it made me wonder why tramlines and other scratches on film are most commonly green. So I reasoned....

Modern acetate positive film has a base later of plastic (that's the strip of 'film' which holds it all together), and three three layers of emulsion on top of it. These are the three colours which make up colour film: cyan, magenta and yellow, and they're each in a very thin layer on top of the film base (here's more about how that kind of colour works).

When the film is projected it passes at rapid and jerking speed through the projector's 'gate', where it can get damaged. The topmost of the three layers of emulsion is the magenta layer, and therefore the most vulnerable to scratching by the workings of the projector.

Now where all three layers of emulsion are fully exposed, you get black film. When the magenta layer is removed, you only have the cyan and yellow layers left. Light passing through cyan and magenta together makes (check the colour wheel) green. So that's why tramlines are green.

I checked with Bryony, and I was right! Soon, Duncan and his mob, with their Christies will have eliminated all dust, scratches and imperfections from the pure stream of digital light. Maybe we're only losing the crackle of the needle on a vinyl LP, maybe something more.

Len Lye, meanwhile, is soon to get his own centre in New Plymouth, very good news for the town that holds the archive of his work and life.

In order to post a comment, please log in:

E-mail:

Password:
Login
Forgotten your password?
Then enter your e-mail in the box above and click: Send Password

Not Registered? Then register here now.