This standard specifies the determination method of chroma of aluminum hydroxide for filler, which is suitable for the determination of chroma of aluminum hydroxide for filler. The measurement range is L *: 80.00~ 99.99; a *: -0.50~ 0.50; b *: -0.20~ 1.30. The method summary includes measuring the Light spectrum reflection factor of the sample under the conditions of D65 standard illuminator and 10 ° field of view. The sample tristimulus values X. Y, Z are obtained by integral operation, and the chroma L *, a *, b * of the sample are calculated according to the colorimetry formula. The required instrument is a colorimeter, and the illumination observation conditions can be vertical illumination diffuse detection (o/d) or diffuse illumination vertical detection (d/o). Samples are pre-dried and their chromatic value is measured under specific conditions.