Producing a Cast: from Mold Creation to Patina

Browse
the catalog
Photo taken in the storage facilities of the Palace of Versailles. Wide shot of our artisans applying the liquid elastomer
Application of liquid elastomer on the Ceres Mattei, also known as Faustina at Versailles

Making a mold

The casting process

Creating the patina

Above: application of liquid elastomer on the Ceres Mattei, also known as Faustina at Versailles
Casting is the faithful recreation of a work of sculpture and is the result of a long, meticulous process that involves creating a mold and then using it to produce multiple reproductions.

Making a mold

Making a mold from a physical imprint

The artisans of the GrandPalaisRmn cast workshop produce molds from original artworks. In order to preserve them, a protective layer is first applied to the entire piece. The statue caster then uses a brush to apply two layers of liquid elastomer. This membrane is made up to around one centimeter thick, depending on the volume being molded. The advantage of this material is that it is elastic, precise and easy to unmold.
Photo taken in the storage facilities of the Palace of Versailles. Wide shot of our artisans finalizing the wooden frame
Finalization of the wooden frame
Finalization of the wooden frame
Once the object is covered in its silicone membrane, all the layers of plaster coating are produced for the different parts of the mold. These hold the silicone in place when the piece is unmolded. A wooden frame supports the coating and helps with unmolding and the handling of the mold.
Read our blog posts about impression-making at Versailles
A view in the workshop: our artisan is removing the mold from a cast of the Veiled Virgin
Unmolding of the Veiled Virgin (PI007386)
Unmolding of Vierge voilée (PI007386)
Once the mold is finished, the artwork is unmolded. This is the most difficult step, as any mistake when handling can potentially damage the original.
A view inside the Louvre Museum at the exhibition site for Psyche Revived by Cupid’s Kiss. Two operators from the GrandPalaisRmn photo agency are performing the 3D scanning. One of the operators is holding the 3D sensor while the second controls the ongoing process on a computer
Processing the digital imprint of Psyche Revived by Cupid’s Kiss (RI017201) at the Louvre Museum
Processing the digital imprint of Psyche Revived by Cupid’s Kiss (RI017201) at the Louvre Museum

3D scanning

The cast workshop also puts its digital technology to use when producing 3D imprints, which have the dual advantage of avoiding direct contact with the artwork, and offering the possibility of making enlargements and reductions. As the definition of the surface offers less precision than silicone elastomer (a difference of 5 microns for a physical imprint versus 200 microns with the use of 3D), digital technology is used only when the original artwork is fragile, or if a change in format of the reproduction is sought.
For more details on this technique, read our article
A view in the workshop. The two parts of the mold are placed on a workbench. Our artisan, in a white jumpsuit, is applying a first coat of plaster with a fine brush in one of the molds
Applying the first coat of plaster in the mold
Applying the first coat of plaster in the mold

The casting process

The GrandPalaisRmn cast workshop has some 6,000 molds used for casting in plaster, resin, terracotta and bronze. Slush casting is the most frequently used technique. Plaster is applied to the mold in thin layers, the first using just plaster, the second reinforced with oakum. A wooden or metal frame is produced to support and strengthen large pieces.
Close-up on the Veiled Virgin. We see the hand of the artisan, holding a scalpel, trimming the cast
Trimming of the Veiled Virgin (PI007386)
Trimming of the Veiled Virgin (PI007386)
When the plaster has set, the cast is removed from the mold. The piece has various “seams” from where the different parts of the mold have been joined together. These are trimmed and then made uniform with the rest of the model to ensure that no traces of the production process are visible.
A close-up of our artisan’s hand applying a patina with a cloth on the torso of the Venus de Milo
Application of a patina on the Venus de Milo (PB002024)
Application of a patina on the Venus de Milo (PB002024)

The patina

The final step in producing a cast involves applying a patina to the raw material to create a surface effect that is as close as possible to the original, giving it the appearance of marble, terracotta, bronze, etc., as well as reproducing an effect of the passing of time.
The GrandPalaisRmn cast workshop employs a team of expert patinors. Creating a patina always involves a close inspection of the original to ensure that the result is as accurate as possible. The patinors work with museum curators to verify the model.