Linen backing

Linen backing is a paper saving process where vintage or fragile posters are washed, attached to acid-free paper, and mounted on cotton canvas.

This technique aims to smooth out folds, repair tears, and neutralize acids that destroy paper. It stabilizes the poster, making it easy to roll or frame. The treatment is designed to be reversible.

Origin

The origins of linen backing have been traced to historical paper conservation techniques used to reinforce large paper maps by adhering them to cloth with a starch-based paste, reducing damage caused by repeated folding and handling. Following the Second World War, similar methods were adapted for the conservation of vintage posters. Conservators found that mounting fragile, acidic posters to an acid-free support paper and canvas provided structural stability, reduced further deterioration, and facilitated the repair of folds, tears, and other damage.

Process

Cleaning

The conservator gently washes the vintage paper with purified water and a mild detergent. This removes dirt, acidic components, and stains. Sometimes a sponge is also used.

Layering

The back of the wet poster is coated with a reversible adhesive. This is usually a natural wheat starch or methyl cellulose paste.

Mounting

The pasted poster is applied to a sheet firmer backing paper. This layer acts as an acid barrier.

Canvas attachment

The backing paper layer is then attached to a stretched cotton canvas or linen backing.

Drying and finishing

The mounted poster dries flat for several days. The conservator then trims the excess canvas, leaving a small border for framing.

Usage

Linen backing is commonly used for three main purposes:

• Preservation: Many vintage posters were printed on inexpensive, acidic paper that deteriorates over time. The conservation process includes deacidification to neutralize the paper's acidity, helping to reduce yellowing and embrittlement.
• Restoration: Tears, folds, and other damage may be repaired by realigning the paper fibers, while areas of loss can be infilled with acid-free paper and, where appropriate, inpainted to reintegrate the image.
• Display and storage: The canvas backing provides structural support, allowing the poster to lie flat for framing and to be rolled for storage with a reduced risk of cracking or further damage.