This coloring page features a large blue and purple door with a big orange knocker in the center. The door has a sign that states "Monster Inc," prompting curiosity about what lies beyond it. To bring out the bright colors of the door and sign, use purple for the door and a lighter shade of purple for the sign. Mix it up by using a bold, deep blue for the door trim and orange for the knocker. Create interesting dimension with light blues and pinks around the door, as if the sky has been painted directly behind it. Add splashes of green and yellow to suggest foliage nearby. To give the page more of a whimsical touch, fill the sky and ground in with bright colors, such as periwinkle blues and jade greens. Finally, outline the door and sign in white to bring out all the colors and details.