Method and apparatus for determining the authenticity of flat objects: banknotes, documents, security labels, and related items

A method for determining the authenticity of a test object security feature, comprising:

• a) in a test object exposing step, exposing the test object security feature to ultraviolet radiation across a range of selected test object excitation wavelengths or frequencies or energies;
• b) simultaneously with said test object exposing step, measuring a test object intensity of radiation emitted from said test object security feature across a range of selected test object emission wavelengths or frequencies or energies;
• c) preparing a test object emission spectrum from test object intensity measurements;
• d) in an authentic object exposing step, exposing a security feature of a known authentic object to said range of selected authentic object excitation wavelengths or frequencies or energies;
• e) simultaneously with said authentic object exposing step, measuring an authentic object intensity of radiation emitted from said authentic object security feature in a range of selected authentic object emission wavelengths or frequencies or energies;
• f) preparing an authentic object emission spectrum from authentic object intensity measurements;
• g) wherein said test object excitation wavelengths or frequencies or energies are the same as said selected authentic object excitation wavelengths or frequencies or energies, and wherein said selected test object emission wavelengths or frequencies or energies are the same as said selected authentic object emission wavelengths or frequencies or energies;
• h) and either i) determining a test object excitation wavelength or frequency or energy that produced a test object maximum emission intensity, determining an authentic object excitation wavelength or frequency or energy that produced an authentic object maximum emission intensity, comparing said test object exposure wavelength or frequency or energy to said authentic object exposure wavelength or frequency or energy, and making a determination that said test object is not authentic if said test object exposure wavelength or frequency or energy and said authentic object exposure wavelength or frequency or energy are not equal within a predetermined margin of error;
• or ii) comparing said test object emission spectrum to said authentic object emission spectrum, and making a determination that said test object is not authentic if said test object emission spectrum and said authentic object emission spectrum are not equal within a predetermined margin of error,
• or i) and ii).