A group of painters abandoned their paint pots, mixing bowls, and compasses as they fled from a villa in Pompeii in the doomed year of 79 CE. The unfinished wall painting they had begun included a scene of cupids engaged in a chariot race, framed by elegant columns and swags of foliage.
Although the artwork itself is incomplete, its discovery nonetheless fills in our understanding of the Roman painting process. Together with other works in progress seen here, it is possible to reconstruct the steps used in the technique of buon fresco (literally, “true fresh”).
This sketch shows the process a painter undertook when beginning a fresco. Faint red vertical and horizontal lines were created by plucking a taut string loaded with pigment across the wall to create a grid. This grid acted as a guide for the artist when sketching an image and likely also aided in scaling up a scene from a sketch onto the wall.
The artist has sketched out two separate architectural compositions freehand, one with a round temple framed by a pavilion and a half arch, and the other an architrave supported by columns. Several of the elements in the sketch appear in works like this one, where embellished architecture is depicted in perspective as if through a window.
Once a design was planned out with sketches on a base layer, painters had to move quickly to apply pigment while the plaster was still wet, to ensure the durability and vibrancy of color. Once the plaster had set, the artists would then add smaller details onto the wall using a different technique, that of secco fresco (literally, “dried fresh”), which required mixing pigments with a binder so that they would adhere.
Some visual programs included relief stucco works. Found in one of the Vesuvian area’s largest villas, which measured over 100,000 square feet, this stucco relief of an athlete resting on a hoop sat at the back of a niche in a nymphaeum (a grotto-like space dedicated to the nymphs). Traces of pigment show that the work incorporated color but was also surrounded by flat painted fresco and actual, painted, and relief architectural elements. Mixing two-dimensional images with sculpture and relief plays with a viewer’s perception of volume, causing them to question the real or artificial nature of a space.
This procedure was carried out by a team of artisans whose identities are largely unknown; wall painters seldom signed their works. Often an expert figure painter created the image’s outline and added details to central panels, while less specialized wall painters worked on the background. Although we do not know the specific identities of these artists, and we can only speculatively attribute the hand of a particular painter across multiple works, it seems likely that the same muralists worked on different buildings throughout the city.
Our knowledge of the Pompeian painters’ process has been reconstructed by archaeologists through a study of the frescoes themselves and through later documents describing pricing and payment schemes. This research suggests a hierarchy between the main figure painter and artisans who worked on the background.
While the names of Roman artisans are largely unknown, in the upper left corner of this work an inscription reads “Alexander of Athens drew,” identifying not only the maker’s name but also his Greek origin.
Marble panels such as this one could be inset into walls as another means of decoration. An inscription above the heads of the standing figures lists the names of characters from the story of Niobe, who boasted about her many children to Leto, the mother of the gods Apollo and Diana. Those deities then punished Niobe for her hubris by killing her children. Here two of Niobe’s children play knucklebones (astragali), unaware of the offense that their mother (at center) has caused Leto (at right).
Plumb bobs, set squares, and compasses were used in different phases of the painting process. While these same tools were also used in construction (to square a wall, for example) and in geographical surveying, the artists’ work was no less precise. Fresco painters frequently began with a sketch of the image intended for the wall, and then used a grid to scale up the size of the image. In order for this process to work effectively and without distortion, the grid itself needed to be drawn accurately. At later moments of the painting process, artists used a plumb line and compass to ensure painted design elements were positioned and shaped correctly.
These plumb bobs are all of a similar and common kind—an inverted cone with a hole at the top through which it was suspended—yet each has a slightly different shape and weight (perhaps influencing its specific usage). Plumb bobs were used to create or confirm the verticality and straightness of a line. The set square was used to draw or check right angles. Compasses were used to create circles, to calibrate thickness, and also to set measurements to a particular scale, especially for repeating motifs or decorative elements.
Chemical analyses of surviving pigments together with period literary sources grant us insight into the types of materials used by painters, as well as clues about the significance of particular colors as signifiers of status. Some colors of the basic palette (black, white, blue, yellow, red, and green) could be made from readily available materials and were provided by the artists, while other, more costly pigments needed to be supplied by the patron above the price of the commission.
Reds and yellows were popular color choices. Ocher, an earth pigment derived from clay, was used to make yellow and red pigments (yellow ocher turns red when mixed and heated with hematite, an iron oxide). Reds could be derived from more opulent sources too, and the naturalist writer Pliny the Elder reports that cinnabar (mercury sulphide), a costly alternative to red ocher, was so desirable that a maximum price was established by law. In fact, cinnabar was twice the cost of Egyptian blue, and Egyptian blue—made with copper ore imported from Cyprus heated with lime and an alkali—was four times as expensive as yellow ocher.
Pigments derived from the plant and animal kingdom could also range in price. Pink was produced from the root of the Rubia tinctorum plant, but purple was far more expensive since the murex necessary for its production in antiquity could be produced only from a specific kind of carnivorous sea snail. Black, commonly made from soot, was a popular background color for many of the grand rooms of Pompeii, yet Pliny also mentions expensive black pigments, including one imported from India.