Microscope Slide - Dimensions and Types

Dimensions and Types

A standard microscope slide measures about 75 mm by 25 mm (3" by 1") and is about 1 mm thick. A range of other sizes are available for various special purposes, such as 75 x 50 mm and for geological use, 46 x 27 mm for petrographic studies, and 48 x 28 mm for thin sections. Slides are usually made of common glass and their edges are often finely ground or polished.

Microscope slides are usually made of glass, such as soda lime glass or borosilicate glass, but specialty plastics are also used. Fused quartz slides are often used when ultraviolet transparency is important, e.g. in fluorescence microscopy.

While plain slides are the most common, there are several specialized types. A concavity slide has one or more shallow depressions ("wells"), designed to hold certain samples such as liquids and tissue cultures. Slides may have rounded corners for increased safety or robustness, or a cut-off corner for automated handling.

A graticule slide is marked with a grid of lines (for example, a 1 mm grid) that allows the size of objects seen under magnification to be easily estimated and provides reference areas for counting minute objects. Sometimes one square of the grid will itself be subdivided into a finer grid. Slides for specialized applications, such as cell counting, may have various reservoirs, channels and barriers etched or ground on their upper surface. Various permanent markings or masks may be printed, sand-blasted, or deposited on the surface by the manufacturer, usually with inert materials such as PTFE.

Some slides have a frosted or enamel-coated area at one end, for labeling with a pencil or pen. Slides may have special coatings applied by the manufacturer, e.g. for chemical inertness or enhanced cell adhesion. The coating may have a permanent electric charge to hold thin or powdery samples. Common coatings include poly-L-lysine, silanes, epoxy resins, or even gold.