Using UV-1900i Plus to Evaluate Raw Materials for Chemical Products Based on the Hazen Color Scale

User Benefits

- The color of liquid raw materials can be quantified in Hazen units. - The spectral assessment feature in LabSolutions UV-Vis Color enables simple evaluation of samples based on the Hazen color scale.

Introduction

The ISO 6271:2015 and the Japanese Industrial Standard (JIS) K0071-1:2017 describe how to measure colors in Hazen units (also called the platinum-cobalt scale or APHA color scale) to evaluate the color of chemical products. The Hazen color scale is used in quality controls and to evaluate the color of samples ranging from colorless or transparent to yellowish. These regulations stipulate preparing platinum-cobalt color standard solutions with 24 different fixed concentrations of potassium hexachloroplatinate (IV) and cobalt (II) chloride hexahydrate that range in color from 0 to 500 Hazen units and then using these standard solutions as reference criteria. The Hazen unit value of a sample is determined either by visual comparisons against these standard solutions or by performing measurements with a colorimeter. The prescribed method for measuring Hazen unit values with a colorimeter involves measuring the transmittance of the 24 platinum-cobalt color standard solutions, using these measurements to calculate XYZ tristimulus values, and preparing a calibration curve based on these values. Samples are then measured to calculate their tristimulus values, and the calibration curve is used to find the corresponding standard solution color and Hazen unit value. LabSolutions UV-Vis Color is an optional software product for LabSolutions UV-Vis that includes a calibration curve created from platinum-cobalt color standard solutions that conform with ISO 6271:2015 and JIS K0071-1:2017. To evaluate a sample based on the Hazen scale, a user just has to analyze the sample, and LabSolutions UV-Vis Color will then calculate the corresponding Hazen unit value.

February 11, 2025 GMT