Because Emco changed the colors all the time, the only source for the original color sits on the Unimat you want to paint.? If someone already paint a different color on it before, you wil never find out the original color of your specific unimat anyway.
If you want to put an register of original colors together, it only works under controled lightning conditions.
That means total manuel control of all camerasettings, total manuel control of all lightning settings and also workingscreen.
Otherwise your register is useless as a color reference
Ruben