User Guide

For an introduction to the application and use of Certified Reference Materials in absorption spectrophotometry



This filter is a useful tool for routinely checking the wavelength and absorbance accuracy of a visible spectrophotometer. Like its liquid counterpart, the didymium glass filter produces characteristic peaks that make it suitable for use as a wavelength reference material in the visible region of the spectrum. In this filter, the didymium is combined with a neutral density filter giving a nominal 1A background absorbance that can be used to check the absorbance accuracy of the instrument


didymium and ndf


9 characteristic and well-defined peaks can be certified, covering the wavelength range from 430 nm to 890 nm. This spectrum is superimposed on a constant background absorbance, nominally 1A.

Peak wavelengths are certified at nominal values of 473, 514, 530, 572, 586, 739, 748, 807 and 879 nm.

The absorbance values, nominally 1A, are certified at wavelengths between the didymium peaks, at 410, 455, 550, 637 and 773 nm.



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.