The content of trivalent chrome has great effect on the quality of chrome plating layers. Not only can measuring and control the content of Cr+3 learn about the performance of chrome plating solution, electric and anodic condition etc, it also can ensure the process of chrome plating .This method is measuring the contents of Cr+3 through Visual Colour Comparison, and this test is convenient, fast and accurate.       Operation process:       Measure the consistency of chromic anhydride in the chrome plating solution first, then according to chromic anhydride consistency(C) ---chrome plating solution quantity confirmation formula: M= 2000/C M--- Milliliter amount of chrome plating solution C--- The consistency of chromic anhydride (g/L)      Calculate the milliliter amount of chromic anhydride picked up, extract corresponding numerical value with pipette and put it into color comparison tube, add water to the scale, shake up, place it to the middle of No.1 and No.2 tube and compare the color below daylight lamp. If the sample color is thicker than that of No.2 tube, please try it between No.2 and No.3 tube, analogy in turn. Then confirm and estimate the consistency of Cr+3 .The consistency is just as following form: Color comparison tube No.1 No.2 No.3 No.4 No.5 No.6 Consistency of Cr+3 (g/L) 0 C×0.5/100 C×1/100 C×1.5/100 C×2/100 C×3/100                C stands for the consistency of chromic anhydride in the form.According to the comparison result, record content of trivalent chrome.               Application example: Certain chrome plating solutions chromic anhydride is 212.48g/L, by calculation, the necessary amount of chrome plating solution is 9.4mL. After color comparison, the color is between No.2 and No.3 tubes, then the Consistency of Cr+3 for No.2 tube is 1.06g/L and the Consistency of Cr+3 for No.3 is 2.12g/L. So the consistency of Cr+3 for this chrome plating solution is between 1.06 and 2.12. According to the color grads estimate, we can confirm Consistency of Cr+3.