Date: 11 Jun 2021
The first, and what is probably the most important step of cleaning an old oil painting, is a thorough analysis of both the condition of the oil painting and of our confidence in our own abilities.
In regard to this analysis there are three main areas to focus on, which are as follows:
- The condition of the layers of paint
- The condition of the canvas, including any wear or tear
- an assessment of the frame on which it is stretched on
However, if any of the following apply then the safest option for restoring the painting without damaging it would be to turn it into a professional:
- If the top layer of paint isn’t just dirty but there are dames or exposed areas reaching the canvas
- If the canvas itself is damaged, for example, if the fabric has been torn or frayed.
- If there is any damage to the stretcher bars or even slight deformation to the wooden frame.
Therefore in this article, we will introduce you to the easiest and safest steps in the restoration of an old oil painting, namely the cleaning of a canvas dirtied with dust and other layers.
Removing any light dust:
So, having made sure none of the damages previously listed apply to your painting, the first step you can take is to remove the top layer of dust that has accumulated on the painting over time.
This could simply be done with a slightly damp microfiber cloth. To dampen the cloth some restorers wrap them in an ordinary disinfectant wipe. Before you start cleaning with this cloth make sure it is not too wet, so it doesn’t disturb the paint on the canvas. Now, you can start gently rubbing this damp cloth along the surface of the painting without applying much pressure, as to not stretch the canvas any further. Keep in mind that this step only removes the very top and newest layer of dust on the canvas.
Any dust which has sat on the painting for a prolonged period of time usually becomes incorporated with the paint, so to remove this we must move on to the next step, for which you need a clean container where you can mix some water with a little soap.
It is recommended to work with distilled water because it’s already been purified. For this step, the amount of detergent is small in proportion to the water. You can check this ratio by mixing the water and soap with a clean finger, if only a few bubbles form on the surface then your liquid is diluted enough, if not considered adding more water to the mixture. Using a finger to mix the water can also help to determine the temperature of the water which should feel lukewarm.
To clean these older layers of dust you can use cotton earbuds. Firstly soak the cotton buds in your mixture and with gentle movements rub them across the canvas in a circular motion. It’s good to start this part of the process in a small corner of the canvas, and seeing how the earbud and canvas react, if the earbud gets dirtier with dust instead of picking up the colour of the paint then its safe to continue this process across more of the painting.
It's important to keep checking this periodically, according to the chemical properties of the paint. Furthermore, it's good to keep changing the earbud regularly to avoid spreading the dirt and dust instead of removing it.
It's possible that the dust will be too old, and thus not be susceptible to cleaning, in which case you can add more soap into your distilled water and do another check on a corner of the canvas. If even this does not change the appearance of the painting it's more than likely that the reasons for this are complex, which would mean it's better to turn in the painting to a professional restorer, who can continue the process after further analysis.
Tobacco smoke and others:
Quite often the dirtying of a painting isn’t just a consequence of the buildup of dust, for example, tobacco smoke is known to stain paintings, leaving them with a slight yellowish tint. Paintings that have sat near or in a kitchen can also become stained over time. In these cases the soap mixture would be ineffective, so to combat this you can use a mixture of distilled water and rubbing alcohol. We recommend you start with a ratio of around 1:3 alcohol to water. To apply this mixture to the canvas, soak your cotton earbuds in the liquid and then gently rub it across the surface of your painting, in circular motions. As with the previous step, it's important to keep checking the state of cotton buds and changing them regularly as they become dirty. If for whatever reason the earbuds start to pick up the colour of the paint, it's best to stop what you’re doing and hand in the painting to a professional before damaging it. However, if this doesn’t happen, but the yellowish tones are still not coming off, then you can begin to increase the amount of alcohol in your mixture and continue cleaning the painting whilst regularly checking for any unwanted results. When adding in more alcohol make sure you keep the amount of spirit below 50% of the mixture.
The last type of dirtying/contamination you might see whilst assessing the damage of an old oil painting is a complex mixture of different sources, especially when you are not aware of what these sources are.
In this scenario, you can use turpentine to clean the painting, by applying it with the same technique as explained previously in the methods including water and rubbing alcohol. When using turpentine, it is even more important to regularly check the cotton bud you’re using to apply the substance onto the canvas, especially when going over new areas.
This is the final effort you can take to renovate an old oil painting, without handing it over to a professional restorer. This means that if despite all our efforts the painting still doesn’t look as good as it could or contamination has remained then the only thing left to do would be to trust a professional to finish restoring it.
Applying a varnish:
After you have finished renovating the painting or have just received it from a professional restorer, you should use a protective varnish to cover the painting, keeping it safe from any other future contamination. Professionals recommend using varnish with an acrylic base since the chemical composition of the acrylic varnish prevents the blending of the varnish and the paint on the canvas, known as ‘migration’.
The acrylic varnish is meant to be renewed every several decades, but its protective qualities are just as effective as other types of varnishes. With this final step, the renovation process is complete, so you can proudly display the painting, for your everyday viewing pleasure.
The restoration of oil painting can hardly be one of the innumerable things which we now call a hobby. Given the deep roots of oil painting in world culture and history, restoration of paintings, as a craft, often requires professional training. The secrets behind this training are probably what excites our curiosity, driving us to revive the history carried through these paintings, whether it be a part of your family heritage or if it was an artwork you adored and purchased.