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Summary:
A previous paper A Contribution Towards a Standard Metrology for the Colorimetric Specification of Printing Inks [1] detailed the colorimetric differences in CIE color notation, between proposed standard condition s and illuminants for the two predominant ink color sets. This presentation is offered as a contribution to the pool of metrology knowledge needed to formulate a colorimetric/densitometric standard for graphic arts inks. The (SWOP) Specification for Web Offset Publication ink set and the International Ink Set (ISO 2846) [3]. This presentation is offered as a contribution to the pool of metrology knowledge needed to formulate a colorimetric/densitometric standard for graphic arts inks. The (SWOP) Specification for Web Offset Publication ink set and the International Ink Set (ISO 2846) [3]. Traditionally, an abridged colorimeter, the densitometer is used as an in-process and quality control device to characterize graphic arts ink-on-paper images. Ink the graphic arts, information on color quality is needed in at least two different points in the print reproduction process. One of these is the raw materials, checking to insure that the proper color ink has been obtained and will be used. Another is in the process quality control checking at the printing stage to ensure print consistency and proper ink film thickness. In the past, densitometry has been used to satisfy both of these needs. However ink sets with very different visual color appearance may produce the same color density values [2]. To insure consistent color printing, the values obtained for a densitometer must directly correlate with the visual color characteristics of the standard ink sets. Densitometers for use in the graphic arts can be purchased with three different filter sets. Each of the sets has its supporters and detractors. It is the intent of this paper to compare data outputs from these densitometer filter sets to each other and to densities derived from spectrophotometric measurements. Using samples for the Munsell Color Notation Atlas, this paper will also explore the ability of the various densitometer filter responses and colorimetry to discriminate between closely spaced color ink on paper images.