How do I select a filter for my application?

The first step is to determine what type of filter is required for the application. The basic types of filters are Color, Shortpass, Longpass, and Neutral Density. Each type of filter has unique characteristics that lend it to one application or another and each is defined in detail in our Technical Library's Glossary. The second step is to determine what wavelengths are of interest. filters are defined by what part of the spectrum they pass or do not pass. For instance, an UV Cutoff (or Longpass) filter is designed to pass both the visible and IR portions of the spectrum, but block (or "cut") the UV portions of the spectrum. See the example below for more information:

Example:

A common application for CCD cameras is to block off the near-IR (700 to 1000nm). Since most light sources emit light in the near-IR, a filter is required to pass only the visible spectrum (400 to 700nm). The type of filter that passes the visible and blocks the near-IR is a Shortpass (opposite of Longpass) filter. We offer IR Cutoff filters that satisfy this requirement.