Like tile, most paint will differ slightly in each lot produced. If you plan to use the same color thoughout your house, it's a good idea to purchase as much paint as you can at one time. This will avoid any deviations in the paint color and save you an extra trip to the store.
When painting with a roller, don’t fill the tray more than one-third full. Also, load the entire roller with paint by rolling slowly down the tray and back, several times.