Measure your target sample using your spectrophotometer and enter the displayed CIE L*a*b* values. Make sure the selected illuminant and observer settings exactly match those used in your spectrophotometer. If you want to evaluate metamerism during color matching and formulation correction, enter the target's CIE L*a*b* values under different illuminants. **Important:** You only need to measure your target sample once. To obtain CIE L*a*b* values under different illuminants, simply change the illuminant settings in your spectrophotometer and record the corresponding values. There is no need to physically measure the sample again for each illuminant. This allows MEC to consider the target's color appearance under multiple lighting conditions when predicting and correcting formulations.