Glossary of terms

xanthometry xanthométrie measurement of yellowness in paper

XYZ see CIE colorimetric system

“Y” internationally used abbreviation for the absorptive primary color yellow, thus also for the technical printing process color yellow.

YCC compression method defined by JPEG and C-Cube for luminance, blue-standardized and red-standardized chrominance; application: JPEG (JFIF), Kodak Photo YCC, YCC tags of
the TIF format (TIFF).

yellowing jaunissement yellowish discoloring of the substrate fibers (proportion of wood pulp) or of the coating through chemical reactions with printing ink components (ghost
images).

yellowness dominante jaune in the sense of opponent color theory, the hues in the yellow area opposite to the blue hues; representation as color space coordinates: b*>0 (CIELAB) and v*>0 (CIELUV); see also blueness, greenness, redness.

yellowness index indice de jaune description of the yellowing of almost white/colorless materials, interpreted as a deviation from the degree of whiteness. For this reason there are 16 standard formulae, including ISO 2470 and ASTM, CIE, DIN and Tappi. More and more frequently, paper manufacturers, instead of specifying yellowness and whiteness, specify the CIELAB coordinate L* or all three color values L*a*b*.

YIQ see color TV