It is also a sure bet that the Egyptian ruling class was lighter skinned than the subject population. That is a universal trait found in all societies. The rulers select lighter skinned mates for their offspring. When a darker usurper takes power, he marries his children off to lighter mates. He takes wives who are lighter. That is true in Mali and Tanzania as much as it is true in France or Alabama.
As a rule, ruling classes spend less time out in the sun than the general population. Thus, their skin tends to be lighter colored (no 'tan').