Friday, June 27, 2014

Zooming in on Microscopic Analysis at SA

Sustainable Archaeology has a new piece of analytical equipment - a Nikon SMZ-25 stereoscopic microscope. We are excited by the versatility of this new instrument, which will allow us to view objects within a range of 6.3 to 315x magnification with both direct and transmitted light sources.
Chad Steele, from Nikon Canada, puts the SMZ-25 together.
No single piece of equipment has arrived at our facility intact - everything from our humidity readers to our microCT scanner, even our building, have arrived in multitudes of pre-assembled pieces. This single microscope was no exception - above is an image of just a fraction of the packaging that this piece of equipment came in.

The SMZ-25 is a fully automated microscope; magnification, zoom and even lighting are mechanically adjusted either on the computer or the separate control unit/monitor. Besides magnification, there are a number of lighting options that increase the versatility of the system. It has a transmitted light source in the base that forces light up through an object, allowing us to view things like thin-sections of ceramic or soil on prepared slides. There is a ring light that sits on the lens, providing even illumination of an object, such as a trade bead, from the top-down. And there are goose-neck fibre-optic lights that allow us to move and adjust the angle of the light source to capture and highlight surface details on an object, such as use-wear on the edge of a projectile point. Oblique coherent contrast (OCC) illumination provides contrast and colour to otherwise clear and colourless objects such as diatoms (microscopic algae) or starch. The unit is also equipped with a 5 megapixel camera for capturing publication-quality images, and the Nikon NIS-Elements software comes with the ability to focus-stack (z-stack) multiple images upon one-another in order to capture a clear image with a greater depth-of-field.

Nikon SMZ-25 stereomicroscope with camera and remote control unit.
We look forward to using the microscope to examine floral remains such as seeds and even pollen, phytoliths or diatoms from archaeological sediments. It will also be used to examine the temper inclusions in ceramics, cut marks on faunal remains, usewear on tools, to identify the species of wood/charcoal samples and even examine fingerprints in clay objects. With analytical software capable of defining regions of interest and morphology, counting, measuring, and filtering, this stereomicroscope makes a valuable contribution to the Imaging capabilities of Sustainable Archaeology: Western.