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The Example of the Crab Louse

Crab Lice as Apparatus Gymnasts? (Calendar 2002)
All pictures from the Calendars 2002-2018 are made by scientific photo-graphers Oliver Meckes and Nicole Ottawa. They have specialized to visualization of scientific artefacts, focused on scanning electron micros-copy.
In 1994 they founded agency »eye of science«. The main instruments are an scanning electron microscope and some powerful computers. Almost all pictures are pohotographed in their own laboratory.

Here comes an example how such a picture was done:
In Germany, crab lice have been almost eradicated. Germans are simply too clean. So fresh material from the domestic front is not to be expected. Oliver Meckes and Nicole Ottawa from eye of science turned to the Tuebingen Institute of Tropical Medicine. The Institute did indeed have a few samples, preserved in 70% alcohol, all the way from Africa. Nice and clean, of course, without hairs.
Certain preparations were necessary so that they could be examined under the SEM (scanning electron microscope). The crab lice were fixed and converted step by step in alcohol (ethanol, graded series 70, 80, 90, 95, 99, 100%). In the case of the crab louse, this took a full day. Then the preparation went into a pressure chamber, where, while being slowly heated to 40 °C at 50 bar, the alcohol was replaced by liquid CO2. Finally the sample was coated with gold under vacuum.
Only by using this complicated procedure can it be ensured that the object does not shrink and go out of shape while drying, or that cells collapse. Later examination in the SEM vacuum requires the object to be free of water and eletrically conductive. Now gilded crab lice were available, but they only look true-to-life if they are in their milieu. So the little creatures were packed into a moist chamber to make their joints a bit movable. Meanwhile, Oliver had cutt off a couple of hairs and sharpened them with the keenest scissors. The crab lice were to hang on to the hairs with their snap hook legs as they do in real life. With the crab louse held in a pair of special soft pincers in the one hand and the hair in a pair of soft pincers in the other, half-an-hour's worth of threading began at 40x enlargement under the stereomicroscope. Threading the hair between the crab louse's legs. The louse in 2 millimeter in length, its leg not even 0.3 millimeter! Once this had been managed, the individual hairs with their loads "only" had to be attached to a sample holder by means of electrically conductive adhesive. After another spattering of gold, into the SEM.
And how did the color get into the picture? An SEM, a scanning electron microscope, doesn't »see« with light but with electrons. Where there's no light there are no colors. The electron-optical pictures can show only the topography of an object, not its color, which is defined by light wave lengths. Eye of science compensated this disadvantage by means of digital image processing. Nicole Ottowa expended a great deal of patience on restoring the color of life to the photographed objects to the very last pixel (when the shot was made everything had in gold). It meant in separating the object hair by hair from the background, to restore the glitter to the Drosophila melanogaster's eyes, or carefully to bring out the bacteria in dental plaque or on the surface of the small intestine. Coloration of a picture can easily take 2 days.
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