Colored Glass Filters

• Wide variety of applications
• Standard Schott glasses for repeatability
• 2” square or 1” round sizes
• Filter mounts also available

Absorbing glass filters are the simplest form of color filter. The transmittance curves for each type of glass are well known and repeatable. Thickness of the filter defines the actual transmission. These filters are ground to a specified thickness and polished to produce a given spectral transmission which is found by applying the correction factor in the table to the diagrams which follow. For filters of different thickness it is necessary to recompute the transmission using the following formula:

T = P(τ₁ (λ))^d/d_o

T = Total filter transmittance
P = Correction factor
τ₁(λ) = Transmittance at wavelength λ
d = Thickness in millimeters of the Ealing filter required.
d_o = Thickness in millimeters indicated above the curve for the material.

In colored glass filters the only effect of tilt is an increase in path length through the filter. For angles of incidence (Ø) less than the Brewster angle (appx 57^o), the new thickness can be calculated as follows:

t_Ø= t_O * n/(√1-sin2Ø)

Temperature change is of little concern in the application of colored glass filters. However, there is a small shift which could affect the performance of sharp cut filters in some circumstances. Normal operating temperature is 23^oC.

Please note that many of these items are on clearance and therefore limited quantities are available. If higher quantities are needed, please contact us.