To ensure reliable performance, the degree of spectral reflection of the calibration white tile is important. Each manufacturer must comply with international calibration standards, but the accuracy of the device itself and the agreement between the instruments (comparison of two or more units of the same model) are directly subject to the accuracy of the calibration procedure. If the laboratory and manufacturers use all similar models of spectrophotometers with excellent matching between instruments, it reduces the time and cost of producing and shipping physical samples….