The painting shows in the background the town of Dordrecht (Dort) from the south-east. The skyline is dominated by the Grote Kerk with the Vuilpoort, one of the town's water gates (demolished in 1864), beyond the windmill to the left. A similar view appears in another National Gallery painting by Cuyp, known as 'The Small Dort'. The church and the water gate are seen from another angle in 'The Maas at Dordrecht in a Storm' by Cuyp, also in the National Gallery's Collection.
This landscape is a mature work, probably of the late 1650s, demonstrated by the exceptional quality of the monumental representation of the cows, three at rest, and one standing placidly observing the milkmaid at work.
Miranda Hinkley (in studio): Housed beneath a glass ceiling that provides optimal light for their detailed work, the Science and Conservation teams rescue damaged and deteriorating paintings. As part of that role, they study how colours change over time, including a pigment that, as I found out, is notorious for aging badly: yellow lakes.
Miranda Hinkley: I’ve come up to the conservation studios to have a look at a painting that’s being worked on at the moment by Aelbert Cuyp, 'The Large Dort' – a distant view of Dordrecht. It has a view across some fields and in the foreground are some cows and some milkmaids and it’s quite a lovely rural scene. How long has it been with you now?
Larry Keith: I’m not really sure – probably about getting on to a year I think, because we work on a variety of different pictures at once, so it’s not only that picture. But there was quite an extensive amount of work to do, thinking about what was going on and doing a lot of analytical work together with the Scientific department, which helped us proceed; so it was slow progress, I think, for the cleaning.
Miranda Hinkley: And it seems that one of the problems with this painting was in fact his use of yellow?
Marika Spring: That’s correct, yes. All the greens are painted in so-called ‘mixed greens’ which means they’ve used a yellow pigment mixed with a blue pigment to make the green and, particularly in the darker greens, the artist has used a pigment called yellow lake. And yellow lake is made using a plant dye stuff. The most common one in the 17th century was a plant called weld, but the trouble with plant dye stuffs is that they’re very vulnerable to fading and that’s what’s happened in this painting. And when we took a sample from the foreground landscape and looked at it in cross-section, perpendicular to the surface of the paint layers, we could see that the top portion of the paint had faded and turned white and that has the effect of creating a sort of misty veil over the foreground landscape.
Miranda Hinkley: Is this issue with yellow lakes a particular feature of Cuyp’s work?
Marika Spring: It was a very common way of achieving green in the 17th century and he’s not the only artist whose paintings suffer this type of deterioration. But a lot of artists mixed other pigments in as well, which has meant that their paintings haven’t suffered quite so badly. But it is a very characteristic paint defect for paintings by Cuyp, that’s for sure.
Miranda Hinkley: But the overall effect is of this really beautiful mustardy yellow and a very, kind of crackly paint surface. What is this actually an image of?
Marika Spring: This is a very high-magnification detail of the lower right foreground of the painting, and here we can see patches of yellow-brown varnish that are left on the surface of the paint. In fact, the rather nice soft grey colour is actually the result of a pigment change in the paint.
Miranda Hinkley: So that’s yellow lakes at work…
Marika Spring: Yes, that’s yellow lakes again, yes, that are faded.
Miranda Hinkley: So what will be your next step in terms of returning the picture to its former glory?
Larry Keith: Well, after the structural treatment has been done – repairs to the canvas itself – the picture will be revarnished and then we’ll start to fill in any losses with the filler to bring it up to the same surface level. And then we’ll do a retouching using not necessarily identical pigments, but certainly the same kind of layer structures if there’s a grey, and then a brown, and then a translucent yellow in the original, for example, we would repeat the same kind of structure to get the same optical effects, with the intention of making our retouching as difficult to see as possible. That being said, with the understanding that you can always see it very readily with ultraviolet light, and the fact that we also document everything in every stage of the treatment so there’s no intention to deceive in a fundamental way, but simply to make the picture read as harmoniously as possible when it goes back on the wall.
Miranda Hinkley (in the studio): Thanks to Larry Keith and Marika Spring.