Recent stratigraphic investigations carried out in the room now used as the Bibliographic Information Office have revealed traces of its original decorative scheme, offering a richer understanding of the space. Although currently used for everyday administrative activities, the surviving evidence clearly suggests that it once fulfilled a more representative function.

The decoration is concentrated along the upper walls, where they meet the ceiling, and extends around the entire perimeter of the room. Such continuous horizontal decorative bands were widely employed between the late 19th and early 20th centuries in formal, though not monumental, interiors. Likely executed in tempera on fine plaster, the paintings use natural pigments applied in thin glazes. This technique produced soft, delicate, layered surfaces capable of modulating light without overwhelming the space.

The surviving decoration includes painted mouldings, linear friezes and stylised vegetal motifs. Although only partially legible today, the designs feature slender tendrils, foliate scrolls and small stylised leaves arranged in orderly, repetitive compositions. These elements belong to a simplified Neoclassical decorative vocabulary typical of the period, where ornamentation is present yet carefully restrained.

Particularly notable is the use of chiaroscuro: subtle shading and tonal gradations create an illusion of depth and relief despite the decoration remaining entirely two-dimensional. Painted frames, for example, appear to project from the wall through delicate contrasts of light and shadow, imitating stucco mouldings.

Although altered by time, the colour palette remains elegant and sophisticated. Ash grey and ochre tones dominate the principal bands, complemented by warmer shades ranging from pale pink to sandy beige. In the ornamental details, traces of olive and grey-green define the vegetal motifs. Originally close to ivory or warm white, the light background helped to diffuse natural light, enhancing the spatial legibility of the room.

Compared with the more monumental rooms, the decorative language here is more restrained and modular, conceived as a continuous frame that complements rather than dominates the architecture. At the same time, the techniques and motifs employed connect seamlessly with the rest of the building, reinforcing the unity of the original design scheme.