Paint can be applied as a solid, a gaseous suspension (aerosol) or a liquid. Techniques vary depending on the practical or artistic results desired. As a solid (usually used in industrial and automotive applications), the paint is applied as a very fine powder, then baked at high temperature. This melts the powder and causes it to adhere to the surface. The reasons for doing this involve the chemistries of the paint, the surface itself, and perhaps even the chemistry of the substrate (the object being painted). This is called "powder coating" an object. As a gas or as a gaseous suspension, the paint is suspended in solid or liquid form in a gas that is sprayed on an object. The paint sticks to the object. This is called "spray painting" an object. The reasons for doing this include: The application mechanism is air and thus no solid object touches the object being painted; The distribution of the paint is uniform, so there are no sharp lines; It is possible to deliver very small amounts of paint; A chemical (typically a solvent) can be sprayed along with the paint to dissolve together both the delivered paint and the chemicals on the surface of the object being painted; Some chemical reactions in paint involve the orientation of the paint molecules. The application of the paint is fairly easily if done correctly. It is the prep work and order of operations that is tedious and detailed. Your first step when painting is to make sure you move all of the furniture, pictures, tables, etc. out of the room and most importantly out of your work space. Next is to lay down tarps or drop cloths to protect your flooring, but most of all if you spill or splash any paint. The next step, wall preparation, is a detailed process which could involve anyth ng from skim coating, spackling, caulking, sanding, priming, taping, etc. After all the prep work has been completed you can now begin painting. Usually your first step in painting should be the "cutting in phase". This phase includes the brushwork around the edges, windows, doors, trim, molding, ceiling or wall line, etc. It is up to the painter of the order of wall spaces he or her chooses to do first. For instance it does not matter if you cut in the ceiling, or paint the window trim first and paint the walls last or vies versa. What is important is that the user cuts in first on every wall space. From there, depending of your order of operation, you can break out the rollers and being rolling the large open space on each wall space. After you applied the necessary amount of coats to the wall, you can remove any tape left behind and clean up. It is recommended that you do not try to wash your walls for at least two weeks after painting to let the paint cure fully. In the liquid application, paint can be applied by direct application using brushes, paint rollers, blades, other instruments, or body parts such as fingers and thumbs. Rollers generally have a handle that allows for different lengths of poles to be attached, allowing painting at different heights. Generally, roller application requires two coats for even color. A roller with a thicker nap is used to apply paint on uneven surfaces. Edges are often finished with an angled brush. Using the finish flat one would most likely use a 1/2" nap roller Using the finish eggshell one would most likely use a 3/8" nap roller Using the finish satin or pearl one would most likely use a 3/8" nap roller Using the finish semi-gloss or gloss one would most likely use a 3/16" nap roller [10]