Altarpiece unclear. Altarpieces can still broadly be divided into two types, the "reredos", which signifies a large and often complex wooden or stone altarpiece, and the "retable", an altarpiece with panels either painted or with reliefs. Retables are placed directly on the altar or on a surface behind it; a reredos typically rises from the floor. Retable-type altarpieces are often made up of two or more separate panels created using a technique known as panel painting. The panels can also display reliefs or sculpture in the round, either polychrome or un-painted. It is then called a diptych, triptych or polyptych for
San Marco Altarpiece of cast shadows towards the bottom edges of the draperies in the painting, which are indicative of how Angelico gave the medieval equation of earthly and heavenly beauty new immediacy by translating it into the rational language of a representational style. In addition, as Angelico implies in other ways, glazing was a technique used to create yet another boundary between the real world and the pictorial illusion. San Marco Altarpiece The San Marco Altarpiece (also known as "Madonna and Saints") is a painting by the Italian early Renaissance painter Fra Angelico, housed in the San Marco Museum of Florence, Italy.