C o l o r T e s t K i t ( D i e t I n s t a l l e d)
(e) Hold the comparator up to a light such as a window, the
sky, or a light and view through the openings in the comparator.
Rotate the disc until and color match is obtained. The reading
obtained through the scale window is multiplied by 5 to obtain the
apparent color in APHA platinum cobalt units.
Color discs are developed to withstand fading due
to ultraviolet light,
but to prolong the life of
the discs, avoid leaving in direct sunlight for
any extended period of time.