ALTANA Liquid Color Standards Manual - Manual (Page 6)

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for oils in this range. These tubes were adjusted
to bring them into line with accepted usage, and
a slight change was made in Tube #6 to equalize
the spacing. This was published as a new method,
DI544-58.
However, continuing problems with production
and standardization of the liquid colors at that
time resulted in demand for glass disks as primary
standards. The method was again revised to
use glass disks whose color is specified spectro-
photometrically as the primary standard. This
revision was published as D1544-63 and descri-
bes the scale used in the Gardner-Delta
Comparator (Catalog #CL-6750).
At the present time, both the liquid and glass
standards meet the requirements of ASTM, DIN,
ISO and other specifications. The choice of
instrument is principally a matter of personal
preference.
General Information