<title>Update on INCITS W1.1 standard for evaluating the color rendition of printing systems</title>

Abstract

The color rendition ad hoc team of INCITS W1.1 is working to address issues related to color and tone reproduction for printed output and its perceptual impact on color image quality. The scope of the work includes accuracy of specified colors with an emphasis on memory colors, color gamut, and the effective use of tone levels, including issues related to contouring. The team has identified three sub-attributes of color rendition: 1) color quantization, defined as the ability to merge colors where needed; 2) color scale, defined as the ability to distinguish color where needed; and 3) color fidelity, defined as a balance of colorimetric accuracy, in cases where a reference exists, and pleasing overall color appearance. Visual definitions and descriptions of how these sub-attributes are perceived have been developed. The team is presently working to define measurement methods for the subattributes, with the focus in 2004 being on color fidelity. This presentation will briefly review the definitions and appearance of the proposed subattributes and the progress to date of developing test targets and associated measurement methods to quantify the color quantization sub-attribute. The remainder of the discussion will focus on the recent progress made in developing measurement methods for the color fidelity sub-attribute.

<title>Scanner-based macroscopic color variation estimation</title>

“…The improvement of the color mapping accuracy indicates that the semi-blind color transformation, T semi−blind : 4 RGBK → 3 L * a * b * , might be suitable for the international standard on macroscopic/microscopic image artifacts, such as mottle and grain, and image color rendition. [7][8][9] Quantifying the macroscopic color variation across pages, on the other hand, only involves estimating color difference across all pages. Furthermore, since the purpose is to accomplish the task without a spectrophotometer, it is only necessary to quantify relative color deviation against their own centroids.…”