Sheen

• Satin paint has a velvety luster, while eggshell has a duller appearance. Eggshell sheen is so named because the color is akin to that of an actual eggshell. Satin gets its name from the fabric. Both of these paints shine a little, but satin shines more than eggshell. Satin shines more because the formula has smaller molecules than eggshell does. Eggshell paint hides wall imperfections better than satin, because less light reflects off the paint. More reflection tends to show imperfections in house workmanship.
  
  

Durability

• Satin stands up better to cleaning than eggshell does. Even though both of these paints have better durability than a flat paint, neither cleans as easily as semigloss and high-gloss. Satin is a better sheen to use on walls or trim in high-traffic areas, because smudges are easier to clean from it. Eggshell also cleans with scrubbing, but not as good as satin. Satin sheds moisture better than eggshell, but both can be used in bathrooms and kitchens, and on exterior surfaces.
  
  

Uses

• Eggshell is better to use in areas with minimal dust and kid traffic. Satin works well in both of these situations. Eggshell is better to use in areas with a lot of light, because its dull characteristics minimize light reflections. Satin reflects more light, and this can be harder on the eyes.
  
  

Coverage and Application

• It takes more satin paint to achieve a satin sheen than it takes eggshell paint to achieve an eggshell sheen. Coverage is less with higher-sheen paints. This means that you would need two coats of satin paint to achieve the coverage that only one coat of eggshell would achieve. Eggshell paint dries faster than satin. Apply both paints with the same tools; but too much back-and-forth over satin blemishes the paint. Eggshell doesn't have as much sheen, so you can work with it a little longer to achieve an even finish.