Preload is the stretch. The amount of volume being returned to the right side of the heart from systemic circulation. Afterload is the squeeze. The amount of resistance the left side of the heart has to overcome in order to eject blood.
"First find out what emotion you want your space to play into -- airy, earthbound, dramatic -- then proceed to choose your color from there," says designer and PPG Pittsburgh Paints color and design adviser Vicente Wolf.