Author: Andy Shield
Oil paintings, particularly antique oil paintings, encounter an array of environmental factors during their extensive lives, which contribute to a decline in their appearance. These include changes in the atmosphere, particularly in terms of temperature and humidity, and also exposure to harmful airborne substances, such as tobacco smoke, soot and general daily grime.
In addition, the surface of an oil painting is also vulnerable to impact injuries, via bumps or sharp objects. For canvases, this can lead to tears, while for panel paintings, dents can occur, which disrupt the way light reflects from a surface.
As with all treasured possessions, they should be handled with care and restored by a professional when required.
When Should An Oil Painting Be Restored?
There are several reasons why oil painting restoration is a sensible idea.
Discolouration & Yellowing
Over the years, oil paintings often become yellowed due to an accumulation of environmental grime, such as smoke and soot. For antique paintings, they were often housed in rooms with roaring open fires and exposed to numerous pipe smokers. At times, the surface can even gather the odour of a smoker.
Discolouration will inhibit one’s enjoyment of an oil painting as it not only reduces its intended vibrancy but it also obscures its sense of depth. For a landscape painting, for example, a distant view would convey less realism. While for a portrait, the contrast of light and shade could be diminished.
Historic Oil Painting Restoration
Prior to the mid-20th century, oil painting restoration was conducted at a fairly trivial level as there were fewer resources on how a painting should be handled. Often, artists were tasked with restoring a painting, which led to mixed results.
In John Constable’s biography by Charles Robert Leslie, it refers to him painting over areas of an old master painting as its new owner wasn’t overly fond of the composition. This was, sadly, more prevalent than we would care to think.
The old restoration techniques have aged poorly, leading to numerous issues, such as the discolouration of areas of retouching. The approach to retouching was also often quite brutal and covered more of the surface than required.
Torn Canvases & Cracked Panels
It feels like the end of the world when a canvas tears or a panel begins to crack. However, in both instances, with diligent care, paintings can be restored and conserved back to their former glory.
Lifting Or Flaking Paint
Most antique paintings display a network of cracks, known as craquelure. This is not necessarily a bad sign and it’s very normal. Some of these are caused by the drying process, while others may occur over the years due to changes in temperature and humidity.
At times, depending on various factors, such as the materials used, paint can crack and lift in areas - e.g. come away from the surface. From here, it can also flake and become detached. In these instances, professional assistance should always be sought to avoid any further damage occurring. There are various ways to resolve this.
How To Restore An Oil Painting
A professional restorer will always undertake a series of tests before committing to any remedial work. These tests may include examining the painting under ultraviolet light and infrared light to see beneath the surface. This has mixed results, depending on the materials used, but in most instances, it can prove particularly useful.
For instance, ultraviolet light can, at times, reveal areas of overpaint above the varnish. While infrared could reveal where the artist has changed their mind during the painting process.
Cleaning & Varnish Removal
For discoloured paintings, decades of accumulated dirt can be removed through cleaning, which takes various forms. At its simplest, a conservator cleans above the varnish, using non-invasive methods, which may be enough. However, in most cases of serious discolouration, the varnish is the problem and needs to be removed.
For particularly old paintings, there could be various layers of varnish, each with their own level of resistance. Solvents and cotton wool swabs are used during this process and each conservator trusts their own set of solutions. Prior to varnish removal, it’s vital to undertake thorough testing as every surface will react differently. Indeed, with paintings by Sir Joshua Reynolds, who was exceedingly experimental, every work needs to be approached as if it’s the first.
A 17th-Century Painting Being Cleaned
Canvas Lining & Relining
When a canvas has torn extensively, or become generally degraded, it may need to be lined. This process involves attaching a newer canvas to the old one with conservation-grade adhesive. The process requires heat, which can be applied by hand or via a heated vacuum table. It should only be conducted by an experienced professional as, if undertaken poorly, the results can be destructive.
For minor holes, these are often simply filled and retouched. While, for small tears, these can be patched.
For particularly old canvas paintings, they may already have been lined. When this is the case, the old lining needs to be removed, along with the adhesive (carefully by scalpel), before re-lining the canvas.
A 19th-Century Painting With A Relined Canvas
Oil Paint Consolidation
When oil paint is lifting and/or flaking, conservators may decide to consolidate the surface. This process involves injecting conservation-grade adhesive under the edges of the lifted paint, before gently pressing them down with a spatula.
Retouching
With any form of restoration work, retouching areas of missing paint is often a requirement. Professional conservators are experienced in working closely, often under magnification and with a small brush, to apply paint millimetre by millimetre. It’s never a case of applying it with spirit and enthusiasm, in fact quite the opposite. Less is always more as the intention is to see as much of the original artist as possible.
At times, particularly for historically important pieces with large areas missing, a conservator may opt to use a hashing technique rather than paint large sections from their imagination. This has the effect of removing the distraction of the paint losses, while also retaining the artist’s hand. In all cases, a conservator will use reversible techniques and paint above a layer of varnish to create a barrier, so if, in the future when another conservator works on the piece, they can clearly identify the different layers. Unfortunately, this wasn’t always the case with work undertaken in the past.
Professional Oil Painting Restoration
In all cases, although it may be tempting to restore your own paintings, it should only be undertaken by a trained specialist. Conservators study for many years to develop their knowledge and, with every new project, their wisdom increases. At Brave, we’ve restored hundreds of works over the years and offer oil painting restoration as a service via our studio, Layers Restoration.