ASTM D6166 Test Method for Color of Naval Stores and Related Products
ASTM D6166 Standard Test Method for Color of Naval Stores and Related Products (Instrumental Determination of Gardner Color)
5. Apparatus
5.1 An instrument capable of measuring transmitted color and reporting the results in the Gardner color scale described in Test Method D1544. If such an instrument is not available, one may be used which is capable of measuring transmitted color and reporting in tristimulus values or chromaticity coordinates using standard illuminant C and the 2° observer, described in Practice E 308.
5.2 Glass Cuvets, 10–mm path length, unless a different path length is specified by the manufacturer, or
5.3 Glass Tubes, clear. Standard Gardner tubes, as described in Test Method D 1544, or other glass tubes designed for a specific instrument may be used. Gardner tubes may provide less accuracy than glass cuvets and should be used only when a decrease in accuracy is acceptable. Glass cuvets should be used for referee situations.
6. Calibration and Standardization
6.1 Calibrate the instrument following the manufacturer's recommendations.
7. Procedure
7.1 Taking care not to touch the measurement area of the sample cell, fill a clean Gardner tube or cuvet with the material to be tested. If the material is cloudy, first filter it.
7.2 Insert the glass tube or cuvet in the instrument and measure the color, following the manufacturer's recommended procedure.
