Brightfield Microscopy
Brightfield microscopy (a dark or coloured sample against a white background) is the simplest of microscopy techniques and is available on three of the microscopes within the Bio-Imaging Facility, the Zeiss AxioImager, Leica TCS SP2 UV and BD Pathway.
Bright field optical microscopy is perhaps the most widely used of microscopy techniques. Specimens are usually mounted on slides and illuminated from below with a halogen lamp which gives a near white light output. Contrast in the sample is caused by absorbance of some of the transmitted light by dense features or from a specific stain.
Brightfield microscopy only requires a fairly basic microscope setup:
- light source, usually a halogen lamp
- condenser lens system to focus light onto the specimen, often Kohler illumination.
- objective lens which collects light from the sample and magnifies it, lenses are often described by their magnifying power ie x20 and numerical aperture (NA), resolution 0.8.
- ocular or eyepiece to collect and further magnify the light from the specimen.
- camera system to record images.
Brightfield images can be acquired on the Leica SP2 UV and BD Pathway machines as an overlay for fluorescent images to provide contextual information.
The Zeiss AxioImager is the microscope most suited to bright field microscopy as a standalone technique as it has a dedicated halogen light source, Kohler (or critical) illumination and a dedicated high resolution colour camera.
