Abstract: A scanner (200) is arranged to detect a unique spectral signature acquired from a sample (230) coded with a security marker (700) made up from one or more overt or covert coloured features (704a-704b) having known and uniquely identifiable spectral characteristics. More particularly, a narrowband light source (218), operating in the middle/near ultraviolet to short/near infra-red wavelength ranges, pulses light onto the security marker fixed to or formed in the sample (230). A lens system (222, 216) collects spectral data for analysis by a processing engine (201), such as a smartphone. The light source (218), which may be an array of differently coloured LEDs (224), selectively illuminates the security marker with discrete wavelengths as LEDs are selectively energized. The coloured features (704a-704d) are realized by combinations of dyes, pigments or inks that may fluoresce that are difficult to replicate and therefore typically pantone-based. The coloured features each have unique spectral responses, i.e.

Abstract: A data carrier, such as a security card or bank card is disclosed having a stripe of machine readable markers formed on it. The markers (10, 12, 16, 18) are different colours, and more precisely, different spectra. By passing light through the markers and detecting the spectrum of a marker, information represented by different spectra can be decoded.