Monitoring sheet material

摘要

The concentration of a selected additive in a web of sheet material is determined by measuring the infrared absorbance at first and second wavelengths at which the absorbance of the additive is respectively a maximum and a minimum and finding the difference of the absorbance measurements. Inorganic constituents of cigarette paper are identified and monitored by scanning a region of the infra red spectrum of the paper, computing first and second order derivatives of the scan, comparing the first and second order derivatives by a best fit comparison with reference spectral data, and computing concentrations in the paper of the identified inorganic constituents.