More playing with crossed polars
by Mike Samworth
As regular readers of my contributions will know, I rather
like looking at objects between crossed polars. Using this
technique (described in previous articles by myself and Dave
Walker) can make otherwise quite drab objects look much more
This first photomicrograph shows scutiform scales of the
coastal plant sea buckthorn to good effect. This is simply with a
piece of polarising material between the light source and the
slide, and another, between the objective and the viewer (or in
this case camera.
Sea buckthorn (Hippophae
rhamnoides) between crossed polars.
However, this not where the fun stops, for there are further
variations on this that can be achieved by inserting something
BETWEEN the two pieces of polariser, most easily done above the
first piece. This has to be a clear material that also has an
effect on the light path. In technical books a quarter-wave plate
would be advocated and in old books this would be a selenite
plate. Both of these can be either difficult to obtain,
expensive, or both. A suitable alternative is at hand though, a
number in fact. Simplest is a piece of thin plastic such as that
used to make petri dishes or even Tic-Tac boxes and the like
(Ferro-Roche chocolate boxes etc. the list could be endless!).
Another is to take a normal glass microscope slide and to put
several layers of sellotape on it. Whatever it is you use, just
place it above the first piece of polaroid (the polariser) and
rotate it. You will see the image change out of all recognition.
Look below at the same specimen as the first, only with a petri
Sea buckthorn scale with crossed
polars and petri dish.
Rotate this further and you get yet another
Try it with some of your favourite polarised light objects
and have fun!
All photomicrographs by Mike Samworth.
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