Patent ID: 7800069

Claim:
A method of determining a weight and/or amount of a conversion coating on a metallic substrate comprising: irradiating said conversion coating with infrared energy over a single broadband spectrum of wavelengths; collecting and detecting sample infrared energy spectra reflected from said conversion coating on said substrate over each wavelength of said spectrum of wavelengths; providing a predetermined calibration model comprising a calibration with respect to model infrared energy spectra comprising said spectrum of wavelengths collected from a plurality of metallic substrate standards and a respective known conversion coating weight and/or amount for each metallic substrate standard, said predetermined calibration model comprising a regression coefficient at each wavelength of said model spectrum numerically processed with each corresponding respective sample spectrum wavelength to create a numerical product at each wavelength of said spectrum; and, determining said conversion coating weight and/or amount based on said predetermined calibration model and said sample infrared energy spectra.