Method, apparatus, and article to facilitate evaluation of objects using electromagnetic energy

A method of verification, the method comprising:

• during a first period, sequentially illuminating at least a first portion of a medium being evaluated with a plurality of bands of electromagnetic energy in a first sequence;
• during the first period, measuring a plurality of responses to the illumination from at least the first portion of the medium being evaluated that is indicative of both a portion of content and a portion of material of the medium being evaluated;
• comparing the measured responses of the first period to a first set of reference responses;
• after the comparing the measured responses of the first period to the first set of reference responses, varying a sequence of illumination used to determine whether the medium is authentic, the varying the sequence of illumination used to determine whether the medium is authentic including:
• during a second period, sequentially illuminating at least the first portion of the medium being evaluated with a plurality of bands of electromagnetic energy in a second sequence, the second sequence different from the first sequence;
• during the second period, measuring a plurality of responses to the illumination from at least the first portion of the medium being evaluated;
• and
• comparing the measured responses of the second period to a second set of reference responses;
• and
• making a determination regarding authenticity of the medium being evaluated based at least in part on the comparison of the measured responses of the first period to the first set of reference responses and based at least in part on the comparison of the measured responses of the second period to the second set of reference responses.