This Reference Material can be used to qualify the Absorbance scale, in the ultra-violet, visible and near-infrared regions of the spectrum (250 nm to 3200 nm) of spectrophotometers with spectral bandwidths not exceeding 6.5 nm.

The transmission characteristics of the filter are determined by the thickness of a metallic coating deposited on a quartz plate. The metallic surface is overlaid by an optically bonded cover plate, to protect it from oxidation, contamination, or physical degradation. We consider the bonded cover plate to be more durable than the overcoating method employed by other suppliers.

The spectrum of these filters is essentially flat from 250 nm to 3200 nm.



Absorbance and Transmittance values are certified at 250.0, 360.0, 465.0, 546.1, 635, 1100, 1700, 2210, 2500, and 2850 nm.

These filters are based on a NIST SRM series whose values follow a sequence of Transmission rather than Absorbance values. Approximate values available are: 92 %T (0.04 A), 50 %T (0.3 A), 30 %T (0.5 A), 10 %T (1.0 A), 3 %T (1.5 A) and 1 %T (2.0 A)
As these filters attenuate the incident radiation partly by reflection, inter-reflections could be generated within the sample compartments of some spectrophotometers. This could affect the accuracy of measurements, and it is recommended that potential purchasers contact the manufacturer of their instrument to check its compatibility with metal-on-quartz filters.


A Certificate of Calibration and Traceability and full instructions for use are provided with each Reference Material. Starna Scientific is accredited to both ISO 17034 (4001) as a Reference Material producer, and ISO/IEC 17025 (0659) as a Calibration Laboratory for optical reference measurements. Starna offers a Lifetime Guarantee on all its Reference Materials.