gallery: Fun with movement in polar photomicroscopy.
by David Walker, UK.
In many still photography genres, the intentional incorporation of movement is widely used. For example, the use of low shutter speeds to show ethereal effects of moving water, light trails of vehicles on busy roads in the dark, in sports or other human activity to show some degree of movement. Not surprisingly, intentional movement doesn't seem to be used to a similar extent in still photomicrography; getting the subject as sharp as possible is usually a prime requirement!
But in one of my sillier moments, perhaps attributable to a long dreary winter in northern England, I had a play with low shutter speeds on my microscope combined with subject movement to see what sort of effects can be created with a selection of prepared slides. The failure rate was high, so ideally suited to digital photography where the instant no cost results can be rapidly assessed and mostly binned!
The most successful images showing movement seemed to be those with a good colour palette but simple structures e.g it suited subjects like crystals that were 'active' under 'crossed polars'. Slides with recognisable structure such as insects and plant sections didn't seem to work too well, for me at least.
'Fuzzy' photomicrographs clearly have little to no scientific merit and those below don't pretend to have much artistic merit, but heh, hobbies should have a 'silly but fun factor' and it was fascinating to see what could be created. When the images sort of worked, I found it more satisfying than manipulating a still image with one of the many effects available in photo-editing software as the images were created solely under the microscope.
Images with rotational movement seemed to be more pleasing than those using the x and y controls of a mechanical stage and all the images below used some degree of rotation. The lighting intensity was typically set for an exposure of 2 - 6 seconds to allow a long enough time frame for some control of the movement. I first tried quite extensive rotation throughout the exposure but that created mainly smeared circles of unsaturated colours with no structure.
Palate of Haliotis, unnamed Victorian mount. Zeiss 6.3/0.08 planachro objective. 4 sec.
Continuous rotation of subject during exposure to illustrate the low contrast, smeared effect.
Not sure if these sort of images had much appeal as all structure was lost.
More pleasing images, to the author at least, were created by keeping the subject still at least once during the exposure to give some structure, with variations of movement included during the rest of the exposure. See examples below.
Areas of black in the still image didn't always create satisfying images on rotation, so a full wave retarder was used with the crossed polars to minimise this. The images below used this method, with various magnifications. Apart from tonal balance adjustment where needed and resize with sharpening, all images were the full camera field 'out of camera'. Using the camera's RAW mode if it has one is useful, as gives a stop or so either way to correct the exposure. This is handy as if an image is liked but the exposure is slightly wrong, it can be tricky recreating the exact same effect.
Acknowledgement: With thanks to John Wells who made the Biosil slides and for which the images below heavily relied on.
(All taken with a Nikon digital SLR, ISO 100 - 200)
Musk ketone melt, Biosil preparation. Zeiss 10/0.22 planachro objective. 2.5 secs.
Two stationary phases in exposure with quite quick rotation through ca. 45 degree angle between each.
As above, different area of slide.
As above. 2.5 secs. Two stationary phases in exposure with rapid rotation through shallow angle between each i.e no rotational smearing seen.
Palmitic acid, Biosil slide. Zeiss 6.3/0.18 planachro objective. 2.5 sec.
Two stationary phases in exposure with rapid rotation through larger angle between each.
Hoof of goat, unnamed Victorian mount. Zeiss 6.3/0.18 planachro objective. 2.5 sec.
One stationary phase in exposure with slow rotation through large angle.
Palate of Haliotis, unnamed Victorian mount. Zeiss 6.3/0.18 planachro objective. 4 sec.
In this image, quick step changes in rotation were made throughout the exposure.
Musk ketone melt, Biosil preparation. Zeiss 10/0.22 planachro objective. Nikon DSLR, 2.5 secs.
Two stationary phases in exposure with slow rotation through shallow angle between each.
Potassium chlorate, Biosil slide. 4 secs, two stationary phases with rapid rotation with a shallow angle between them.
Glycine, Biosil slide. Zeiss 6.3/0.18 planachro objective. 6 secs, stepped rotational changes with shallow angle.
Published in the February 2008 edition of Micscape.
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