We wanted to showcase this set of cards we printed recently to demonstrate the difference between embossing and debossing. The artwork for both were identical, the only difference was how they were printed.
Embossing (top) is when the image is raised on the paper - think certificate or diploma. This is done with a die + counter and is done without ink or registered to foil. We use metal plates which are slightly more expensive but hold finer detail.
Debossing (bottom) is the effect that occurs with deep impression letterpress. The image or design is pressed into the paper and can be done with or without ink (blind). We print letterpress designs with photopolymer plates.
Check out all of the photos in the full post including some instagrams of embossing with a registered foil.