Tattooing is not just decoration or a fashion trend; it is a profound cultural, historical, and anthropological marker. Recently, scientists conducted a unique study on fragments of tattooed human skin preserved in the “Luigi Cattaneo” Anatomical Collection at the University of Bologna. These artifacts, dating back to the 19th century, carry astonishing stories: from signs of deep religious devotion to the stigmas society branded criminals with. The results of this work not only allowed for the development of preservation protocols for these fragile specimens but also enriched our understanding of Italian tattoo culture from the century before last.

A Dark Legacy: Why Tattooed Skin Was Collected

Interest in human tattoos among scientists peaked at the turn of the 19th and 20th centuries. During this era, tattoos were viewed not as art, but as objects for medical, legal, and anthropological study. It was then that a dark, little-known practice emerged in criminology and anatomy: the collection and preservation of tattooed skin fragments, which raises serious ethical questions today.

Italian and French criminologists systematically studied the tattoos of prisoners, linking them to narratives of moral decay. This trend was spearheaded by the famous Cesare Lombroso. In his seminal 1876 essay, “The Criminal Man” (L’uomo delinquente), he proposed the theory that tattooing was one of the “anatomical anomalies” indicating innate moral degradation. According to Lombroso, a criminal who tattooed himself was regressing to a “primitive and savage state.”

The Cattaneo Collection, like many other anatomical and criminological collections of the time, became a repository for such “evidence.” The fragments, mounted on wooden panels (inventory numbers 67a and 67b), display both religious and overtly erotic subjects, reflecting the classification of tattoos adopted by Lombroso and his followers.

Loreto Tattoos: A Mark of Faith on a Pilgrim’s Wrist

However, not all 19th-century tattoos were associated with criminality. A significant portion of the studied specimens relates to a unique cultural practice: Loreto tattoos. This tradition was geographically tied to Central Italy and the pilgrimage to the Holy House of Loreto, where, according to legend, angels transported the Virgin Mary’s house from Nazareth.

Pilgrims, often from peasant and rural backgrounds, tattooed their forearms or wrists as a permanent ex-voto (offering) and a sign of deep faith. It was a kind of “medal” that could not be stolen, and a physical connection to the Passion of Christ.

• Subjects: Images of the Madonna of Loreto, the Crucifixion, the Sacred Heart of Jesus, symbols of the Eucharist, and sometimes the year of the pilgrimage (one fragment, 6A, shows the date 1881).
• Technique: Tattoos were applied using wooden clichés that served as stencils, and then the design was pricked with a sharp stylus into which ink (usually blue indigo or black carbon) was rubbed.
• Prohibition: The practice was so widespread that it did not attract the attention of anthropologists studying “primitive” peoples. However, on November 25, 1871, the municipality of Loreto officially banned tattooing, due to both sanitary reasons and the influence of positivist ideology seeking to eradicate “superstitions.”

X-rays and IR Spectroscopy: Secrets of Old Inks

To preserve and catalog the artifacts requested for the exhibition “TATTOO – Tales from the Mediterranean” at the MUDEC museum in Milan (2024), the team of scientists employed non-destructive testing methods such as Infrared Spectroscopy (IR) and Macro-X-ray Fluorescence Analysis (MA-XRF).

Pigment Composition:

The analysis allowed for the precise identification of the materials used by 19th-century tattoo artists:

1. Black Pigment: The main colorant turned out to be carbon black (soot), likely obtained by burning organic materials. The absence of significant inorganic elements confirmed its organic origin.
2. Red Pigment: On the fragment depicting the Madonna of Loreto (1A), the co-presence of lead (Pb) and mercury (Hg) was detected. This indicates the use of minium (Pb₃O₄) and/or cinnabar (HgS)—traditional but toxic pigments. Cinnabar, being expensive, was often mixed with other oxides to reduce cost or enhance color.
3. Brown/Reddish Pigment: High levels of iron (Fe) and manganese (Mn) were found on the fragment with the erotic subject (5B). This suggests the use of burnt umber or natural ochre—natural earth pigments.

Preservation Secrets:

Spectroscopic data also revealed how 19th-century anatomical preparators treated the skin for long-term storage. Intense traces of calcium carbonates and carboxylates, as well as gypsum, were detected. This points to the use of lime (calcium oxide or hydroxide), a traditional agent for dehydrating and treating skin, similar to that used in parchment production. Furthermore, traces of zinc compounds were found, which may be related to the use of zinc chloride (ZnCl₂)—a known antimicrobial and disinfectant agent at the time, used for embalming and preserving anatomical specimens.

Conservation and Cultural Context

The chemical data obtained formed the basis for a complex restoration strategy. Given the fragility of the material, the fragments were compared to parchment. Conservators performed dry cleaning, removed traces of oxidation from metal fastenings, and used controlled humidification to smooth the skin. Lost areas were filled with Japanese paper, and the fragments were remounted on the original panels, but using museum board and removable fastenings to prevent further damage.

The restoration of these artifacts is of great significance. It allows modern researchers to see how tattooing evolved from a stigma of social deviation and a sign of religious fervor to what it is today—an “intimate expression of identity.” The Luigi Cattaneo Collection continues to serve as a bridge between the dark history of criminology and the modern understanding of tattoos as a complex, multifaceted cultural phenomenon.