CCI Notes 10/1

Cleaning Paintings: Precautions

Introduction

Over time, the image of a painting may become difficult to see or the colours may become obscured. The two primary causes for this are a build-up of dust, dirt, and grime (e.g., soot or nicotine), and a gradual yellowing and cracking of the varnish layer.

No one without formal training in paintings conservation should attempt to clean a painting. Accurate interpretation of the effects of various cleaning agents on a particular painting requires a thorough understanding of the materials present in each layer of the painting and extensive practical conservation experience. Otherwise, damage can occur that may not be immediately apparent. For example, applying water or a solvent to a painting with a soluble ground may weaken adhesion to the support, later resulting in flaking paint. Water may cause the fabric layer to shrink, which then may lead the paint layer to buckle and heave. If incorrectly applied, solvents can dissolve the paint and thus destroy the image.

Commercial Products

Never use commercial "painting cleaner" or "picture restoring" preparations on paintings. These preparations are not designed or used by professional painting conservators.

Liquid or paste applied to a painting is rarely, if ever, restricted to contact with only one layer. Access to all layers is available through visible and invisible cracks and through porous materials. Consequently, the effects of a cleaning solution or paste must be considered not only in relation to the dirt, varnish, and paint layers, but also in relation to a painting's ground, size, and fabric support.

Modern Art

Approach paintings in non-traditional media with even greater caution than more traditional works. For example, experience in paintings conservation departments has shown that acrylic paintings can be extremely vulnerable to cleaning. In some instances, the paint can be removed by both water and mild organic solvents. In addition, some modern works might even be affected by brushing.

Small Stains, Marks, and Graffiti

Do not attempt to remove even a minor blemish from a painting. Any, disruption in the surface resulting from inexpert attempts to clean may cause an even more unsightly spot. More importantly, this may result in permanent damage to the painting.

Dusting

Even dusting a painting carries special risks, including the risk of removing paint. Some paintings develop a condition of "micro-flaking", where tiny flakes of paint become partially detached. Not immediately visible, these flakes can be swept away by even the lightest dusting. Larger flakes can also be difficult to detect because they can be camouflaged by the painted image. These too may be easily removed during dusting.

Never use dry or moist dust cloths, stiff bristle brushes, or feather dusters to dust a painting. Threads from dust cloths may catch on areas of raised paint (impasto), moisture may cause subsequent loss of paint, and both bristle-haired brushes and feather dusters can scratch the surface of a painting.

Summary

Cleaning paintings is one of the most demanding areas of paintings conservation, requiring skills acquired through extensive formal training and practical experience. Permanent damage may easily result from even the most cautious attempts to clean a painting by untrained personnel.

Copies are also available in French.

Texte également publié en version française.

^* If you require a plug-in or a third-party software to view this file, please visit the alternative formats section of our Help page.