The value of the readings of tint and shade by the Lovibond
tintometer[66][82][83] has not been commensurate with the labor
involved, but it is necessary to make a record of the reflected tint and
shade[50] of some waters. The standard color disks used in teaching
optics may be used for the purpose.
_Procedure._—The white disk supports three movable standard color
sectors, red, yellow, and blue, and one movable black sector. All are
mounted on a device which can be revolved rapidly, blending the colors
into a uniform tint or shade. A scale around the circumference of the
disk is used to indicate the percentage of each color or white or black
in the blend.
Place the sample in a battery jar on a white ground; adjust the sectors
so that when blended the tint or shade will match the reflected tint or
shade of the sample. Report the percentages of red, yellow blue, white,
and black in the blended tint or shade.