There are various reasons as to why a painting may appear to be dull.
In many cases, oil paintings are simply unvarnished or varnished with a matt varnish. This means that they do not have the same glowing finish and heightened saturation of those with a gloss layer. With more modern or contemporary paintings it is good to keep in mind that they may be intentionally darker, with some artists choosing to paint with muted tones. [You can read more about different types of oil painting varnish here].
In other cases, the painting may have discoloured over time, due to a natural ageing process of historic varnish. Originally, varnish was made from tree resin, which degrades over time as any natural product would. Today, we use synthetic resin in varnish, to ensure that there is no yellowing or discolouration in the future.
Paintings can gather surface level dirt, dust and contaminants. This can often be easily removed with a gentle clean. However, this should still be looked into by a professional, as the dirt can sometimes be beneath the surface and not so readily available to remove with a light cloth.
Staining from nicotine is a common issue, with artworks gathering a thick coat of brown and yellowing discolouration. This is an issue with many historic paintings, which have faced environmental factors such as frequent smoking indoors, as well as open fireplaces building up a stubborn layer of soot.
Paintings can also be affected by direct sunlight, the UV rays disturbing the colour of the paint and in some cases, such as with watercolour paintings, fade the original artwork heavily.
Moisture damaged paintings
Damp conditions can severely dull down a painting, with oil paintings being susceptible to an effect called blanching. This is when the varnish appears to have a white veil covering it, often trapped under the surface. This, as well as any issues associated with mould, will have to be professionally treated to avoid further trauma to the artwork.
Transforming a dull painting
Results for heavily stained or dull paintings can be tremendously exciting, as they reveal areas of the artwork which have not been seen for decades. After a clean and varnish removal, we can often see entirely new items, backdrops and details.
As well as preserving the painting in it’s best condition, art restoration can breathe new life into a painting which could have otherwise been seen as dull. The pigment of skin upon a portrait or the detail of a vast landscape can become entirely more vibrant once they have been brought back to their original state.