FLAT PAINT reflects little light. It looks rich and velvety, especially in deep colors. It doesn’t show all the imperfections in plaster or drywall. It’s great in a living room or a room frequented by adults who do not damage or touch their walls. It’s the least washable. Most builders use flat paint when you buy a new home.
SATIN PAINT is a step shinier than Flat. It’s one of the less common sheens. A lot of paints jump right up to eggshell from flat. It’s usually pretty close to eggshell.
EGGSHELL PAINT is a little shinier still. It is very popular as an all-around sheen. Not too shiny but still pretty washable. Good for offices, bathrooms, and public areas and rooms with kids in them with dirty little hands.
SEMI-GLOSS PAINT is good for doors and trim. It’s not super shiny but still gives a nice glow to the painted surface. Bathroom and kitchen walls do well in semi-gloss because it is even more washable than eggshell. The problem with semi-gloss is it shows drywall imperfections.
GLOSS/HIGH GLOSS/PLASTIC GLOSS are very shiny paints. They often look good on older traditional woodwork. The flaws really show with this paint but that can also be part of the beauty.