The color of the chart was derived from systematic testing in the 1960s. When Ogden and his students were developing the Standard Celeration Chart, red, orange, yellow, green, blue, purple, and violet inks were printed and used in order to evaluate charter preference and performance. Of the participants, the general color preference was green. But the light blue chart produced the highest accuracy and was more resistant to eye-fatigue, so the decision was made to print all Standard Celeration Charts light blue from then on.
Historically, Behavior Research Company has used PANTONE 310 C and PANTONE 311 C for printing charts.
The original color runs are shown below.
