Sunday 6 March 2011: Cross Polarisation - 2
Following the earlier Blip a number of people asked for more information on how to achieve this effect. If you already have a polarising filter then you are well on the way.
For the scientific explanation of what's happening have a look at the comment left by andmoff on my previous Blip.
Traditionally the process involved placing the plastic object between two sources of polarising material. One source would usually be a sheet of polarising film on a Lightbox or other light source, and the other one simply a photographic polarising filter on the camera lens.
However your PC offers you an alternative and cheaper way of achieving this effect as LCD computer monitors contain polarisers.
So the monitor can be used instead of both the lightbox and the sheet of polarising film. Just create a file of mid to light grey and display it Full Screen.
Then find a way of placing the plastic object in front of the screen.
Use the camera with the polarising filter to focus on the object, with the grey screen filling the background.
Now rotate the filter to get the result that pleases you most. Normally its best to let the background go totally black. Experiment with different objects and settings to get something you are happy with.
(The plastic objects here are the two halves of a tape dispenser).