It is designed to measure the color of the varnish, thinner and other transparent liquids.
Take a certain amount of ferric chloride hydrochloric acid solution, potassium dichromate sulphuric acid solution, and cobalt chlorite hydrochloric acid solution, The above three solutions will be mixed together at a certain percentage in order to get 18 solutions with different colors and densities. Then put them into the tubes and sealed separately.
The visual method is used to assess via the comparison with a series of anvil standard tone scale solution，which is marked with the color gradation number. The result is shown in 1-18.