9 OPTICAL AND ELECTRICAL DEVICES, INTRUMENTS OR APPARATUS; OPTICAL AND ELECTRICAL DEVICES, INSTRUMENTS OR APPARATUS FOR USE IN DISTINGUISHING COUNTERFEIT ARTICLES; OPTICAL AND ELECTRICAL DEVICES, INSTRUMENTS OR APPARATUS WHICH MAY BE USED FOR DISTINGUISHING COUNTERFEIT ARTICLES COMPRISING ONE OR MORE OPTICAL FILTERS; OPTICAL FILTERS INCLUDING THOSE COMPRISING THIN FILM AND MULTI- LAYER STRUCTURES; OPTICAL FILTERS COMPRISING PIGMENTS; OPTICAL FILTERS WHEREIN THE TRANSMITTANCE VERSUS WAVELENGTH CHARACTERISTICS OF DIFFERENT OPTICAL FILTERS ARE COMPLIMENTARY; OPTICAL FILTERS WHICH WHEN OVERLAID PRODUCE A CHARACTERISTIC OPTICAL EFFECT; ANY OF THE AFORESAID OPTICAL FILTERS IN COMBINATION WITH OPTICAL AND ELECTRICAL DEVICES, INSTRUMENTS OR APPARATUS WHICH MAY BE USED FOR DISTINGUISHING COUNTERFEIT ARTICLES, INCLUDING ELECTRICAL INSTRUMENTS OPERABLE IN THE INFRA-RED; ANY OF THE AFORESAID OPTICAL FILTERS IN COMBINATION WITH A SUBSTRATE INCLUDING POLYMER SUBSTRATES AND GLASS SUBSTRATES; SCANNING EQUIPMENT FOR USE IN AFORESAID OPTICAL AND ELECTRICAL DEVICES, INSTRUMENTS OR APPARATUS; OPTICAL BAR-CODES; INCLUDING PARTS AND FITTINGS FOR ALL THE AFORESAID GOODS