Like its liquid counterpart, the holmium glass filter produces characteristic peaks that make it suitable for use as a wavelength reference material in the UV and visible regions of the spectrum (240 nm – 640 nm). Unlike the liquid cell, however, It is not adopted by all the Pharmacopoeias for wavelength qualification.
It is accepted for this purpose by the following bodies:
United States Pharmacopeia
American Society for Testing and Materials
Therapeutic Goods Administration (Australia)