Photomicrographs are a type of technical photography, which simply means taking a picture through a microscope. Geologists use Petrographic Microscopes, which are modified for optimal rock analysis by the addition of a rotating stage, polarizing light and other specialized features. The rock samples are thin sections, rock slices only microns thick and mounted on glass slides. I have taken photomicrographs with a variety of systems: Leica-Leitz (by far the best optical system), Nikon, and Olympus. Examples of each are shown below. Olympus proved to be the best of the affordable systems (Leitz microscopes cost twice as much as Nikon or Olympus). And when I find myself with a spare $20,000 to burn, I’ll have my own Olympus microscope-camera system.
Polarized (top) and non-polarized (bottom) images of the same thin section; taken with a Nikon system. Samples from Mt St Augustine, Alaska. Film: Kodachrome
Polarized (top) and non-polarized (bottom) images of the same thin section; taken with an Olympus system. Andesite samples from Tisingal Volcano, Panama. Film: ENC-II
Polarized (top) and non-polarized (bottom) images of the same thin section; taken with a Leitz system. Peridotite samples from Ichinomegata, Japan. Film: ENC-II
The lab shots simply show macro photography close-ups of rock slabs, highlighting the textures of the samples. Sometimes similar shots are taken in the field.
Garnet Lherzolite Xenolith from Kimberly, South Africa.
Camera: Minolta X-700
Lens: Rokunar f2.8 50 mm Macro
Another interesting type of Lab Photography is making ‘maps’ for the electron microprobe. This consists of placing the thin section in a photo enlarger and exposing a projection onto a sheet of photographic paper. I will show an example in Part III where it will become more apparent why one might need to do this.