QuadTech Inc., has unveiled the first web-fed, in-line inspection system that measures colour on both paper and unsupported packaging film, the manufacturer announced in a statement to the press. The new, enhanced version of the company's Inspection System with SpectralCam enables continuous, in-line monitoring of virtually all web-fed package materials, including transparent and translucent substrates.

John Cusack, product manager at QuadTech, explains why accurate in-line colour measurement of film posed a great challenge: "Film material, being unsupported, is less stable than paper as it is more susceptible to fluttering and wrinkling during production. The fluctuating distance between sensor and web makes it almost impossible to attain constant results. Furthermore, idlers, though stable, are prone to contamination, which would negatively affect measurement accuracy.

"We have solved the problem by developing an innovative supporting device, positioned between the idlers. Its vacuum system stabilizes the web on to a low friction surface, enabling the web to maintain a stable distance from the camera at the point of measurement."

The SpectralCam camera uses 31 bin spectrophotometer technology to measure spectral response and calculates accurate Lab. The system measures up to 72 colour targets within the work.