Inasmuch as the Nessler scale[62] and the natural water scale[22][49]
which agrees with it except for colors less than 20, have been largely
used in the past, the old results may be converted[117] into terms of
the platinum standard by means of the ratios in Table 3, but they must
not be considered as universally applicable as the variable
sensitiveness of the Nessler solution introduces an uncertain factor.
Table 3.—VALUES FOR CONVERTING COLORS BY THE NATURAL WATER SCALE INTO
COLORS BY THE PLATINUM STANDARD IN PARTS PER MILLION.[B]
───────────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────
Modified │ │ │ │ │ │ │ │ │ │
Nessler or │ │ │ │ │ │ │ │ │ │
natural │0.00.│0.01.│0.02.│0.03.│0.04.│0.05.│0.06.│0.07.│0.08.│0.09.
water │ │ │ │ │ │ │ │ │ │
standard. │ │ │ │ │ │ │ │ │ │
───────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────
Platinum-cobalt standard color.
0.00│ 0│ 2│ 4│ 6│ 8│ 9│ 11│ 13│ 15│ 17
.10│ 18│ 19│ 20│ 20│ 21│ 22│ 23│ 24│ 24│ 26
.20│ 26│ 27│ 27│ 28│ 29│ 29│ 30│ 31│ 32│ 32
.30│ 33│ 34│ 34│ 35│ 35│ 36│ 37│ 37│ 38│ 38
.40│ 39│ 40│ 40│ 41│ 42│ 42│ 43│ 44│ 45│ 45
.50│ 46│ 47│ 47│ 48│ 48│ 49│ 50│ 50│ 51│ 51
.60│ 52│ 53│ 53│ 54│ 54│ 55│ 56│ 56│ 57│ 57
.70│ 58│ 58│ 59│ 59│ 60│ 60│ 61│ 61│ 62│ 62
.80│ 63│ 64│ 64│ 65│ 66│ 66│ 67│ 68│ 69│ 69
.90│ 70│ 71│ 72│ 73│ 74│ 75│ 77│ 78│ 79│ 80
1.00│ 81│ 82│ 82│ 83│ 84│ 84│ 85│ 86│ 87│ 87
1.10│ 88│ 89│ 89│ 90│ 91│ 91│ 92│ 93│ 94│ 94
1.20│ 95│ 96│ 96│ 97│ 98│ 98│ 99│ 100│ 101│ 101
1.30│ 102│ 103│ 103│ 104│ 105│ 105│ 106│ 107│ 108│ 108
1.40│ 109│ 110│ 110│ 111│ 112│ 112│ 113│ 114│ 115│ 115
1.50│ 116│ 117│ 117│ 118│ 118│ 119│ 120│ 120│ 121│ 121
1.60│ 122│ 123│ 123│ 124│ 125│ 125│ 126│ 127│ 128│ 128
1.70│ 129│ 130│ 130│ 131│ 132│ 132│ 133│ 134│ 135│ 136
1.80│ 136│ 137│ 137│ 138│ 139│ 139│ 140│ 141│ 142│ 142
1.90│ 143│ 144│ 144│ 145│ 146│ 146│ 147│ 148│ 149│ 149
2.00│ 150│ │ │ │ │ │ │ │ │
───────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────
Footnote B:
Zero on the true Nessler scale is about 15 on the platinum scale.