9. Procedure
9.1 Place a sample container or containers, filled to a depth
of at least 50 mm with distilled or deionized water, in the
compartment or compartments of the colorimeter through
which the standard glasses will be observed. Place the sample
in its container in the other compartment. (When using a
three-field comparator, this will be the middle compartment.)
Cover the containers to exclude all exterior light.