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 aesthetically pleasing.

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 dish.

Sea buckthorn scale with crossed polars and petri dish.

Rotate this further and you get yet another effect.....

Try it with some of your favourite polarised light objects and have fun!

All photomicrographs by Mike Samworth.

If any reader wishes to ask about any of the above, or to comment, please do get in touch by contacting me Mike Samworth.

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