Microscope Filters Explained

Microscope filters are used for both observation and photo microscopy. Each microscope filter is used for a different purpose and all are typically placed in the light path, either over the illuminator or in a filter slot that lies in the light path. Some microscope filters are placed in a filter slot in the illuminator box if an external illuminator is used. Below you will find common microscope filters and their intended uses. Shop all microscope filters here.

Green Interference Filter: Achromat and Plan Achromat microscope objectives are best corrected spherically for green light. This means their performance improves with the use of a green filter. Phase contrast objectives are also created to give the best phase images in green light.

Daylight Blue Filter: The daylight blue microscope filter is for observation use only. It provides a pale gray-blue hue to the field of view and is often used to balance the light created by tungsten or halogen microscope lights to balance out the color of the microscopy light. The daylight blue filter was not created for use with photomicrography with daylight color film. Daylight color film requires a blue conversion filter that will boost color temperature of the light source and simulate light of daylight color temperature quality required for daylight balanced color film.

Ground Glass Filter: This microscope filter is often placed over the illuminator to give a more even and diffused light. Ground glass microscope filters are often used with a tungsten light source.

Neutral Density (ND) Filter: The neutral density microscope filter is used to reduce the light by a percentage. There are different numbers listed on the ND filters such as ND8 or ND50. ND50 means that the light is reduced by fifty percent. Neutral density filters are often used in photomicrography.

Didymium Filter: This microscope filter is known as an enhancing filter. The didymium filter is made of didymium glass for increasing the intensity and saturation of red objects. Since thin sections of biological tissue are often stained with one or more dyes to enhance visibility of features in the specimen, if taking photographs of these specimens it is desirable for the stained colors to appear in the photo. While most stains show up well on colored film, there are several that appear washed out. A didymium filters helps combat this washed out problem.

Yellow Filter: The yellow microscope filter is commonly used to fine-tune the color balance of tungsten and halogen microscope light sources for photomicrography with color film. Additionally, there are several metallurgical microscope applications where the yellow filter is helpful in identifying failures in metal structures.