Shade selection for the laboratory. I prefer to use three shade tabs in a photo, as it allows the lab technicians to compare the shades to each other, as well as the adjacent teeth. I also find it negates the need to color calibrate monitors with the lab. Dentaltown - Using e.max Press to Mask a Cast Post. Using e.max Press to Mask a Cast Post. Dentaltown Message Board Cosmetic Dentistry http://www.dentaltown.com/MessageBoard/thread.aspx?s=2&f=101&t=240084&pg=1&r=3653766.