Neutral Density Glass Filters
| Description | Neutral density glass filters, solid filters, certified |
| Use | Checking the photometric accuracy (absorbance) in the visible range (440 nm to 635 nm) |
| Material | Filter material NG 11, NG 5, NG 4 supplied by SCHOTT Glaswerke |
666-F2, 666-F3 und 666-F4 Neutral Density Glass Filters
For decades SCHOTT has been using neutral density glass filters in the Vis spectrum for testing the photometric accuracy and linearity.
They provide a relatively constant transmission overthe visible wavelength spectrum and are calibrated at the following wavelengths: 440.0 nm, 465.0 nm, 546.1 nm, 590.0 nm, 635.0 nm
If desired, other wavelengths are also possible. The thickness of the filters is determined such that there is a stepping of the absorption values from approx. 0.25 A, 0.5 A and 1 A.
Typical spectrum of the neutral density glass filter, taken with a slit width of 1 nm