Les Fleurs du Mal – Small Library

The wallpaper in the Small Library of Trakošćan Castle has hung on the wall since 1856. For nearly 170 years visitors admired it without knowing that it was poisonous. The title borrows from Baudelaire’s Les Fleurs du Mal, published in 1857, a year after the wallpaper was hung, and to the same paradox: beauty that carries poison within it.

Research conducted within the Gardens on the Castle Walls project identified copper (II) acetoarsenite, an arsenic-based emerald-green pigment widely used in the nineteenth century, within the wallpaper’s surface layer. This finding established the material’s hazardous composition and informed the development of appropriate conservation and occupational safety protocols.

The wallpaper was produced by applying finely cut, dyed wool fibres to an adhesive layer, creating a textile-like surface. Microscopic analysis revealed the irregular orientation of the fibres, consistent with historical mechanical flocking rather than modern electrostatic application.

Detached original fibres were collected during cleaning, separated from surface contaminants and reapplied according to the documented pattern using a water-soluble adhesive. No new flocking material was introduced; the surviving original material was reused for reintegration.

The story of the wallpaper is also told in the interpretative film Les Fleurs du mal in which the flowers on its surface speak of their own making, their beauty and their poison.

Photographs before and after conservation: