A range of conformance filter sets allowing quick and simple conformance checks on Lovibond® instruments is available for the principal colour scales. Each filter set consists of coloured glasses representing a spread of colours from the scale of interest which are mounted in holders suitable for the instrument being used. These are supplied with a certificate of conformity stating the actual values for each filter. The conformance filters are provided in sets since good practice for conformance checking dictates that users should be testing either side of their measuring range and ideally within it as well. If necessary, single conformance filters can still be supplied under the category of "Single Filter (Certificated)"
Conformance filters are assigned a nominal value and the company always endeavours to match this value as closely as possible. On occasion, because of the unique manner of the glass making process, it may not be possible to match the requested values exactly. The values achieved and the performance tolerances expected will, of course, always be reported.