Relation Between Visual Color Differences and Tristimulus Color Readings for Pureed Carrots, Spinach, and Pears

Abstract

SUMMARY A range of colors for spinach, carrots, and pears was produced by blending samples of different colors and diluting with water. The samples were examined by a visual panel under a MacBeth Examolite to determine the “just noticeable color difference” (JND) and were then measured with a Colormaster differential colorimeter and a Color‐Eye calorimeter. The JND figures were 1–2.5 delta‐E units calculated by the Adams chromatic value equation. Repeatability figures on the instruments above were respectively 1/2 and 1/4 of the JND values for spinach and pears. For carrots, the repeatability and JND figures were of the same order. Repeatability figures for 4 other calorimeters were lower or approximately equal to the JND figures, indicating that several of the calorimeters could be used to determine color differences as well as an average visual panel.