Unless the Sun Was directly above you then you guys aren't getting the same light.
Thus the Zaino is looking darker.
It think you have just found the "difference." All the pictures were taken in the same light. On silver at least from the pictures, and from the comparison IMHO zaino "darkens" the silver giving it more depth as you can see in the 1st and last pictures. Also, in the last picture you can see the eric's image is more visible(son the zaino car, then the meguair's car. Just like eric said the car has not been washed sinced the week before last. All I have done is wipe it down with water.
