From the Color Mode list, select the color mode you want to map the custom color to.
Click the Add button in the Custom Spot Color Mapping toolbar.
To modify a Custom Spot Color Mapping:
Select the Custom Spot Color Mapping that you want to modify.
Click the Modify button in the Custom Spot Color Mapping toolbar.
Enter or edit a name for the color in the Color field.
Enter the values for each of the process colors in the color mode selected.
Click the Color Chooser button to pick a system color that closely matches the desired color.
Select the method you want to use to narrow down the color:
Click the Measure Color button to use a colorimeter to measure the desired color.
Under Measure Device Setup, select the type of measuring device and the port to which it connects.
Click Calibrate to calibrate the device.
Click Measure to measure a sample of the desired color with a colorimeter.
Click OK.
Click the Print Swatch button to print a swatch table containing swatches that closely match the desired color.
Select the type of font you want the swatch table labels to use.
From the swatch table, select the coordinates of the color that closely match the desired color and enter them into the Closest matching swatch fields.
Click Update Color to update the values for the process colors in the color mode selected.