I purchased a home with flat paint. Even though the home is only 2.5 years old, I decided to have the house repainted with the same color in an eggshell so that it was more washable. It turned out well, or so I thought.

Approximately 12 - 14 days past painting, I moved into the home. I noticed a dirt smudge about 3.5 feet up the wall in the hallway. I used plain water on a soft, clean white cloth to remove the dirt. It took no pressure to remove the dirt. However, this cleaning left a large mark where I wiped the wall. The area is now very dry, and the mark is there. What is going on? Is this my fault? Should eggshell paint act this way? Any advice appreciated.