Most galleries will label the pictures they buy and sell. A gallery label can tell you a number of things, including which galleries have owned the painting and — if you’re lucky — the year they bought it. A good name can be fantastic for provenance, and can really add to a work’s value. In London, I look out for labels from dealers such as The Fine Art Society and Richard Green, though there are several names that are key players in the market.

Exhibition labels are also important to look for: if a painting has been shown at somewhere significant — such as London’s Royal Academy — it only emphasises its importance. An exhibition label can also lead us to original reviews, allowing us to see how a painting was first received, which is always interesting, and a good addition to catalogue notes.

2. Follow chalk marks and barcodes to trace a work’s journey
through the big auction houses

When trying to learn more about a painting, chalk marks form an integral part of the jigsaw puzzle. Sotheby’s has always used yellow chalk to mark pictures, which can offer some clues about a work’s history. Since its foundation in 1766, Christie’s has used stencil marks, which allow you to see who has bought and owned a work over the course of its history; many of these marks date right back to the very first consignment. They are a fascinating insight into previous owners — with more interesting owners having a positive effect on value. The information you can draw from the back of a work can be vital for deeper research into provenance; archives such as those held at The Witt Library allow you to trace a long way back.

3. Don’t believe everything you read

Inscriptions (anything written on the back of the painting) can be a variety of things, from the title of the work, to the artist’s name. Caution is advised, however, as inscriptions can be misleading. Some will say that the picture is by an artist who didn’t paint it, or that the work represents somewhere or someone that it does not. A name written on a work could be the artist’s, but it could also be their partner, a member of the family, an art dealer, or anyone else — there is any number of possibilities. 

4. Take time to assess the lining for possible signs of restoration

Thomas Jones (1742-1803), An extensive landscape with houses seen from the Porta Pia, Rome, circa 1778. Oil and pencil on paper. Sold for: £164,500. Main image at top: reverse showing loan labels, exhibition labels, framer and restoration labels

Unlike the front of a piece, the back of a work will often allow you to see whether it’s been lined or not, with the lining being central to the work’s condition. You can tell a picture has been lined if it has had another canvas put onto the back of it. It’s a good indication that a work has been restored, which is not necessarily a bad thing, but isn’t always a good thing either. It basically means the piece has been damaged at some point and restored — to what extent requires further investigation. Sometimes a work is lined because it’s had a lot of work done; sometimes, a lining is added just to stabilise the work, or in response to a very small amount of damage.

5. It’s always possible to discover weird and wonderful things

The reverse of a 16th century oil painting, showing the brand of the city of Antwerp — a pair of hands above a castle — indicating the work’s support was approved by a guild of panel makers. The mark dates from 1617, when new regulations required guilds to register a symbol — with 22 official makers listed. Regulations drawn up by the Antwerp Joiners’ Gild stated ‘every joiner is from now on obliged to punch his mark on frames and panels made by him, on pain of a fine of three guilders’

What lurks beneath the back of a painting can often be as surprising as what is marked upon it. Though it’s incredibly rare, there have been cases where paintings have been found hidden behind other works — sometimes for hundreds of years, escaping the attention of galleries and auction houses. A loose lining, or an unusual run of nails can be a clue, though sometimes these secret masterpieces are only revealed when a work is reframed. It’s impossible to say why a work is hidden in this way: it may have been a way to store and preserve a work, or it might simply be that the frame was repurposed.

Where reframing would be difficult, improvements in imaging technology have allowed experts to see through the top layers of a work to any original paintings or drawings below; it has not been uncommon for penniless artists to reuse canvases.