Quick Tip : Colors with a deep base

Typically when a color is dark it's important to use a dark primer. Most stores recommend gray. The store rep should tell you this, but sometimes you get a new employee that does not know or they are just not paying attention. For this reason it's good for you to be prepared before your purchase. 

From the pictures above you can see a good example of a dark color blue that needed a gray primer applied first. These walls took three coats. Without the gray it could have easily took 4 or 5.