Roman Red Gloss ware was produced in Italy from the 1st century BCE to the end of the 2nd century CE. Much of this work was produced by using fired clay molds. A bowl would be thrown in the desired shape for the exterior of the finished bowl. This bowl was then decorated on the inside using various stamps and rollers, leaving incised decoration on the interior of the bowl. This bowl was then fired, without any added terra sigilata, and could then be used as a mold for mass produced bowls. The artisans would use these bowls by pressing clay into the mold, smoothing out the inside of the clay with a rib, creating a pleasing interior surface, and then the bowl was left inside the mold until it had dried enough to be removed without damage. At this stage, feet and handles would have been added (perhaps made in their own mold) and the bowl was then set aside to dry. Once the piece was dry, a red clay terra sigilata would have been applied to the bowl, giving it both a pleasing color and a sealed surface, and then the bowl was thoroughly dried so that it could be fired. Many of these wares show several makers marks on them, including the stamp of the factory, the mold makers stamp or signature and the mark of the bowl maker or finisher, demonstrating the industrial process involved in the making of these vessels.
What is interesting about these pieces is how they reflect on the size of the Roman empire. While molds had been used in earlier times as demonstrated by the rams-head Greek drinking vessel pictured below (the rams head part would have been made using a clay mold, while the upper cup portion was produced on a potter's wheel), they had never been used on such a large scale and by so many people. Many Red Gloss wares bear the mark of one producer, but chemical analysis of the clay has shown that the same mark was produced in several different locations (early brand-name recognition). During the time that these wares were produced in Italy, there were many factories producing similar wares through out the Roman Empire. The production of this type of pottery continued in North African even through the Islamic conquest of the area.