Visual and infrared graphic applied through dedicated halftoning for transparent polypropylene packaging

摘要

In the security managing of packaging infrared transparent graphics on polypropylene material is involved. Preparing of dual images of objects, textual messages in visual-V and NIR-Z domain is extended with dual separation which defines new flexographic procedures of colour mixing. Profiles describing and defining V and Z twin pairs are strictly associated with printing conditions. Quality of twin pairs is achieved with spectroscopic analysis of measuring light absorption in visual and near infrared spectrum. Halftoning algorithms support transparent flexographic foil that does not absorb printing inks and does not penetrate into the printing media. Line halftoning element with ''knee'' effect is developed to additionally demonstrate the plasticity of primary objects or letters. The balance between equalizing of inks in the visual domain, and their differentiation in NIR-Z spectral domain is achieved. Relatively coarse shape and structure of screening elements, low ruling, is suitable for additional transparency of graphics, so that the underlying goods packed in foil can be observed. Secondary, hidden graphics is accessible through NIR camera technology. In that way multiple security options are ensured.