Estimation of colour of varnishes, boiled oils and thinners
1 Subject content and applicable scope
This standard specifies the method for estimating the colour of transparent liquid by visual colour comparison with Gardner colour differencemeter or Lovibond tintometer. The colour of the liquid is expressed by the colour scale number of the Gardner colour differencemeter or the Lovibond chromaticity value.
This standard is applicable to the estimation of colour of varnishes, boiled oils and thiners.
2 Normative references
GB 9761 Paints and varnishes—Visual comparison of the colour of paints
3 Method A Gardner colour differencemeter method
3.1 Method summary
Place the sample in a glass test tube and evaluate the result by visually comparing the sample with a series of standard colour scale solutions of Gardner colour differencemeter, marked with colour scale number.
3.2 Materials and instrument
3.2.1 Colourless glass test tube, with an inside diameter of 10.75±0.05 mm and a height of 114±1mm.
3.2.2 Gardner colour differencemeter
3.2.3 Artificial sunlight colour assessment booth or wooden dark box;
3.2.3.1 The technical requirements of artificial sunlight assessment booth shall conform to GB 9761.
3.2.3.2 Wooden dark box: with a dimension of 600 mm×500 mm×400 mm, as shown in Figure 1. Divide the dark box into the upper and lower parts with a ground glass with a thickness of 3 mm. The ground surface of the ground glass faces downward to make the light source uniform. Evenly arrange two 15W daylight lamps in parallel at the upper part of the dark box, mount a light barrier at the front, and leave the front of the lower part open for inspection. The inner wall is coated with dark black paint.
