For the unexperienced painter, heading into a paint supply store can be a daunting task. There are so many decisions to make – first there is the color, then there is figuring out how much product will be necessary to paint the room(s). After all of this, however, comes the final question from the employee – one that many paint customers don't even expect:
"What sheen would you like that in?"
To which many customers reply, honestly: "What do you mean?"
Sheen simply refers to how "shiny" the paint will appear on the wall once it dries. It is much more than simply an aesthetic technicality, however. Different sheens serve very different purposes around the home, and really should be chosen rather carefully.
Commonly there are five different sheens of paint (though the names of some of them might differ from company to company – the basic idea remains the same): flat, eggshell, satin, semi-gloss and gloss.
Flat - Just as the name suggests, flat paints will have practically no shine to them after they have dried. While many homeowners choose a flat paint because of its smooth, dull appearance, be warned that flat paint, in most cases, collects dirt, and is not scrubbable. It may be considered washable, but attempting to scrub a scuff-mark out of flat paint can easily ruin the finish itself and make it necessary to repaint. Having some sheen gives paint a "protective" coating that allows one to wash and scrub stains off walls to their heart's content. Flat sheens are most commonly used on ceilings.
Eggshell - For those who want a flat look but want a bit more protection, an eggshell sheen is the way to go. Providing the warm, smooth look of a flat paint, while adding just a touch of sheen for protection and allowing it to be cleaned, eggshell is often the preferred sheen for interior walls.
Satin - A step up from eggshell, satin is great for kids' rooms, where frequent cleaning of the walls might be necessary. It is often also used in some kitchens. While it has a tendency to make walls look a bit "shiny," satin sheens offer plenty of rewards in terms of making life easier.
Semi-Gloss - Semi-Gloss sheens are, to put it bluntly, generally reserved for bathroom or kitchen use. Any room that has a tendency to collect moisture and mildew should be painted with a semi-gloss sheen, as the thick, shiny film which develops on top of the paint keeps water, mold and mildew from penetrating the surface, making it easily cleanable. Paint stores often also sell a "mildicide" additive that can be mixed into the paint itself, making it even more resistant to mildew for a certain amount of time.
Gloss - The glossiest of sheen has perhaps the fewest of all uses. Often times reserved for craft projects, automotive or outdoor uses, gloss sheens dry harder than any of the others, and, just as their name implies, harden to a very shiny finish, making it difficult to justify using in most indoor applications. Many paint brands do not even carry standard gloss bases in their indoor paints.
Knowing what sheen each project needs is an important first step, but an important thing to remember is that once a specific brand and sheen of paint has been chosen, it tends to be not entirely compatible with other brands. One company's plain, white eggshell paint will surely differ slightly from another brand's even if they are labeled the same. Unfortunately, this means that one should either stick with the same brand of paint, or completely cover everything with the new brand. Just as custom-matched colors are generally very close, but rarely perfect, so also sheens tend to be the same in principle, but are rarely exact.
So, that's that. This should be enough information to allow the average painter to know enough about different paint sheens to help make an informed decision about what is necessary for each individual job.
Now, if only it was that easy to get the whole family to agree on a color.