ASTM D6045 Color of Petroleum Products by the Automatic Tristimulus Method
11. Report
11.1 Report the following information:
11.1.1 The color of the sample as either Saybolt color to the nearest whole number or ASTM color according to the following procedure: (1) for results with decimal numerical values of x.1 to x.4, precede the value with the capital letter "L" and change the decimal value to x.5 (for example, for 3.1-3.4, report L3.5 ASTM color); (2) for results with decimal numerical values of x.5, report as stated (for example, for 3.5, report 3.5 ASTM color); (3) for results with decimal numerical values x.6-x.9, precede the value with the capital letter "L" and round up to the next larger whole value (for example, for 3.6-3.9, report as L4 ASTM color); (4) for results with decimal numerical values of x.0, report as stated (for example, for 4.0 report as 4.0 ASTM color); (5) for results greater than 8.0, report D 8 ASTM color.
11.1.2 If the sample has been diluted with kerosine, report the color of the mixture followed by the abbreviation Dil.
11.1.3 When the sample has been filtered, add the words "(sample filtered)".
12. Precision and Bias
12.1 A correlation has been derived between the manual Test Method D156 Saybolt color and the manual Test Method D1500 ASTM color, and this automatic method in a cooperative program involving five laboratories and ten petroleum materials. Data were generated in 1993 and details and statistical analyses are on file at ASTM Headquarters.
12.2 Precision - The precision of this test method as obtained by statistical examination of interlaboratory test results
is as follows:
12.2.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty):
12.2.1.1 r = 0.14 Saybolt color units (Test Method D156).
12.2.1.2 r = 0.10 ASTM color units (Test Method D1500).
12.2.2 Reproducibility - The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty:
12.2.2.1 R = 1.24 (correlation with Test Method D156).
12.2.2.2 R = 0.48 (correlation with Test Method D1500).
12.3 Bias:
12.3.1 There is no bias in the correlation between this test method and Test Method D1500.
12.3.2 There is no bias in the correlation between this test method and Test Method D156 in the range from 0 to +30. There is a bias for the range from 0 to -16.
13. Keywords
13.1 ASTM color; automatic colorimeter; color measurement; petroleum products color; Saybolt; tristimulus
