Sizing – Definition, Examples, History & More – Art Conservation and Restoration Glossary

I. What is Sizing?

Sizing is a process used in art conservation to prepare surfaces for painting or other artistic applications. It involves applying a material to the surface of a canvas or paper to seal it and provide a suitable surface for the application of paint or other media.

Sizing materials can vary depending on the type of surface being prepared and the desired outcome of the artwork. The purpose of sizing is to prevent the absorption of paint or other materials into the surface, allowing for better control and manipulation of the medium.

II. Types of Sizing Materials

There are several types of sizing materials commonly used in art conservation, including rabbit skin glue, gelatin, acrylic mediums, and PVA (polyvinyl acetate). Rabbit skin glue and gelatin are traditional sizing materials that have been used for centuries in art conservation.

Acrylic mediums and PVA are modern alternatives to traditional sizing materials, offering similar sealing properties with the added benefit of being more stable and less prone to yellowing over time. Each type of sizing material has its own unique properties and is chosen based on the specific requirements of the artwork being conserved.

III. Application of Sizing in Art Conservation

In art conservation, sizing is typically applied using a brush or roller to ensure an even and smooth application. The sizing material is diluted with water to achieve the desired consistency and is applied in thin layers to build up a suitable surface for painting.

Sizing is often applied to both the front and back of a canvas or paper to provide additional support and stability. This helps prevent warping, cracking, and other damage that can occur over time due to changes in humidity and temperature.

IV. Importance of Sizing in Restoration

Sizing plays a crucial role in the restoration of artworks by providing a stable and durable surface for painting and other artistic applications. Without proper sizing, paint and other materials can be absorbed into the surface, leading to discoloration, deterioration, and loss of detail.

By applying sizing to the surface of a canvas or paper, conservators can ensure that the artwork remains in optimal condition and retains its original appearance for years to come. Sizing also helps protect the artwork from environmental factors such as moisture, dust, and UV radiation.

V. Challenges in Sizing

One of the main challenges in sizing is achieving the right balance between sealing the surface and allowing for the absorption of paint and other materials. If the sizing material is too thick or applied too heavily, it can create a barrier that prevents the paint from adhering properly.

Another challenge is ensuring that the sizing material is compatible with the materials used in the artwork, such as the paint, canvas, and other components. Using the wrong sizing material can lead to delamination, cracking, and other forms of damage that can compromise the integrity of the artwork.

VI. Best Practices for Sizing in Art Conservation

To ensure successful sizing in art conservation, it is important to follow best practices that have been established through years of experience and research. Some key best practices include testing the sizing material on a small area of the artwork before applying it to the entire surface.

It is also important to apply sizing in thin, even layers and allow each layer to dry completely before applying the next. This helps prevent the buildup of excess sizing material and ensures a smooth and uniform surface for painting.

In addition, conservators should carefully monitor the condition of the artwork after sizing to identify any issues that may arise, such as cracking, yellowing, or other forms of deterioration. By following these best practices, conservators can effectively protect and preserve artworks for future generations to enjoy.