Both bright field and dark field microscopes are optical microscopes that employ light to view a sample and magnify it, but the similarities end there. The working principle of both the microscopes is entirely different.
Optical microscopes employ visible light and a series of lenses to magnify the specimen and view it in detail. A bright-field microscope uses light rays to create a dark image against a bright background.
While on the other hand, a dark field microscope operates on the opposite principle of a bright field microscope, and the entire field of view appears dark when there is no specimen and once a specimen is placed, it appears bright over this dark background.
Bright Field Microscope Vs Dark Field Microscope
|Parameter||Bright Field||Dark Field|
|Image Formation||Works on the principle of absorption of light. Light is focused on the specimen and it absorbs the light and the contrast image that is dark is viewed against a bright background||The entire field of view appears dark when there is no specimen and once a specimen is placed, it appears bright over this dark background|
|Type of Image||Dark image against a bright background||Bright image against a dark background|
|Types of specimens||Fixed specimens are viewed and are typically stained||All live specimens can be viewed even without staining them|
|Specimen Preparation||Is complex as the specimen needs to be stained||No need of a stain|
|Color of specimen||Appears blur or dark (depending on the stain used)||Specimen appears bright|
|Background of specimen||Background is bright||Background is dark|
|Types of condensers used||Abbe Condenser, Variable focus Condenser, Achromatic condenser.||Abbe Condenser, Paraboloid condenser, Cardioid Condenser.|
|Extent of viewing||It shows the internal as well as the morphological structure of the specimen||It shows the external structure of the specimen|
|Cost||They are inexpensive||They are comparatively expensive|
|Opaque Disc||Not present||Present|
|Utility||It is very easy to use||It is comparatively complex to use|
|Ability to study Minerals and Metals||This microscope can’t be used for the study of minerals and metals||This microscope can be used to study minerals and metals|