Proposal for a New Separation Method for Reproducing Images with Properties in the Visible and Near-Infrared Spectrum

Abstract

Painting dyes and artworks exhibit duality with different states in the visible (V) and near-infrared (Z) spectrum. “V” denotes the solar spectrum ranging from 400 to 750 nm, while “Z” indicates the solar spectrum up to 1000 nm. The infrared state of an artwork can be an independent, “hidden” image. The paper demonstrates a new procedure of graphic preparation for the separation of process inks for reproducing artworks in monographs, with a focus on integration in the visible and near-infrared spectrum. The practical part of the paper uses the Projectina PAG B50 forensic scanner, which is equipped with 24 filters for blocking light from 220 to 1000 nm. Image reproduction involves photography of artwork in RGB, then conversion into CMY, with the addition of K from the Z image. “VZ” separation is introduced into the reproduction of the artwork, simulating the dual states of the original artwork. The GCR procedure is applied by subtracting CMY but based on information for the K component that is equal in the Z image. This process provides a deeper understanding of artworks and offers extended information about their state in the visible and near-infrared part of the spectrum.