In this step, enter the measured CIE L*a*b* values of the sample you prepared in your laboratory. **Important:** Make sure to use the same spectrophotometer or colorimeter that was used to measure the original target, with the same measurement geometry and instrument settings, to ensure consistent and reliable results. MEC automatically displays the illuminants and observer settings previously defined for the target color. These settings are fixed and cannot be changed during formulation correction. For example, if you entered the target's CIE L*a*b* values under three different illuminants, the same three illuminants will appear here. Enter the measured values for each illuminant, then click **Use for Correction** to proceed with the formulation correction process.