ASTM D6756 Standard Test Method for Determination of the Red Dye Concentration and Estimation of the ASTM Color of Diesel Fuel and Heating Oil Using a Portable Visible Spectrophotometer
11. Procedure
11.1 Prepare the filter spectrophotometer for operation in accordance with the manufacturer's instructions.
11.2 Equilibrate the sample to between 20 °C and 25 °C.
11.3 Without filtering the sample (see 13.6), fill a clean, dry specimen cell. The external optical surfaces shall be clean. If not, wipe clean and dry with a piece of lint-free paper (for example, lens paper).
11.4 Insert the specimen cell into the cell chamber of the instrument.
11.5 Record the Solvent Red 26 equivalent concentration and the estimated ASTM color.
