Color Filter Glass

Colored filter glasses, each with its own spectral characteristics for transmitting and absorbing light at various wavelengths of the visible spectrum, are available in a variety of filter types. This type of optical material is most commonly used in cinematography, clinical chemistry, fluorescence microscopy, lighting, machine vision medical instruments, optoelectronics, and spectroscopy applications. The strict control of material thickness achieves precise filtering of the spectrum across a large bandpass. Material thickness can be calculated using transmittance simulation software available from the material manufacturers.

Filters are available in several transmission/absorption options such as:

• Bandpass filters – allow a portion of the spectrum to transmit while absorbing all other wavelengths.
• Longpass filters – allow a longer portion of the spectrum to transmit while absorbing all other wavelengths
• Shortpass filters – allow a shorter portion of the spectrum to transmit while absorbing all other wavelengths.
• Multiband filters – allow transmission of several wavelength bands to pass through.
• Notch filters – reject a small portion of the spectrum, while transmitting all other wavelengths.
• Edge filters – allow the wavelengths on either side of the cut-on to transmit.
• Neutral density filters – evenly reduce transmission across a portion of the spectrum.
• Contrast enhancement filters – promote the intensity of certain colors primarily.

Glass filters are physically and chemically stable, and they are more durable in comparison with plastic and film filters.  The precision of transmission and absorption can be increased by adding a multilayer coating.

The table below shows comparable materials from different manufacturers.