A structural repair of Rubens's Het Steen | Behind the scenes in Conservation

My name is Britta New and I'm one of the conservators here at the National Gallery. I carry out all aspects of conservation and restoration treatments on the paintings here, but my specialism is in the structural repair of the wooden panels that we have. We're looking at Reuben's Hepstein. My colleague Larry Keith has finished cleaning it recently and he's passed it on to me to make the structural repairs, make an initial assessment of what's needed, but also to look at the original construction that Reuben's panel makers used to put the panel together. The Hepstein was painted on a panel made from oak. Oak was the usual material for wooden painting supports in the north of Europe at the time and Reuben's panels tend to be made from this species. In southern Europe in countries such as Italy, paintings actually tend to be executed on poplar. Oak and poplar panels have got very different properties in terms of strength, durability and their propensity for woodworm infestation and they also tend to have very different construction requirements because of these properties. Before the project started I had done some initial assessments of what we thought we needed in terms of repair and had already looked a little at the construction, but it was very difficult to see what was going on in the panel because the way this layer of what's called alabastine has masked much of the reverse of the panel and we need to be able to see that in order to carry out these sorts of assessments. So the first job really for me is to remove this coating layer. The safest way to remove the alabastine coating is to moisten it slightly and scrape it off. So here we're using an aqueous silica gel and we brush that on and very quickly scrape it off again. It doesn't take long for it to hydrate the coating and we don't want the moisture to get into the back of the panel so it's quite a quick process and it's very effective. Now this alabastine was put on in about 1950 following a big damage to the panel that happened in 1947 when there were some great frosts in London and this panel had a very severe damage. It was split all across the entire panel between different boards and caused a lot of damage. Now the alabastine was put on the back as an attempt to imitate the original chalk coating that has been damaged but is still evident on the back of the painting and we can see it quite clearly across much of the painting. Now that was applied really as a means to regulate the uptake of moisture into the back of the painting to try and stop too much movement of the wood that happens when there are big fluctuations in relative humidity. We now have incredibly good air conditioning throughout the galleries and that stops a lot of problems of this type that we don't really face so much anymore. So the painting was made in three stages. The first campaign started off as being a panel made in the normal way made out of three boards and the grain was orientated horizontally. It was then during the second campaign enlarged on both sides and along the bottom and the way that they enlarged that panel is actually quite important and significant to us. If you try and join two end grain pieces of timber like this it's a very very weak join so what they actually would have done is made a half lap join like this which is much stronger. It has a much greater surface area touching but it does mean that what we see on the reverse is different from what we see on the front and that makes it a little bit more difficult for us to understand where the joins are and what we're seeing on the x-rays and the different imaging techniques that we can use to try and decipher the construction of the painting. What's also quite difficult to decipher is where you have a butt join of two planks like this. If they've been well joined it's very very difficult to actually see that join and we're still looking to try and verify where we believe some of those joins are in the way the painting has been constructed and sometimes that makes a difference in terms of where splits might be opening up or where we would want to place supports on the reverse when we're looking at how we're going to support the painting by itself because it's not going to be a panel that's self-supporting. For the size of this panel it's very very thin and that's really to do with I think the the three campaigns of construction because it started off as a much smaller painting that wouldn't have needed to have been so thick and then as different parts were added on and the panel grew sort of fairly organically it wasn't made any thicker and for us now it means that it's really quite a fragile panel because it's so thin in comparison to the size and we have to be very mindful of that when we're thinking about the treatment. Interestingly on this painting we have got some non-original additions on the panel. We've got an addition across the bottom that is probably popular, we're not absolutely sure about that because the painting was in Genoa for a time so we think there might have been some additions made then. There's also an addition on one side and that addition has been put against the grain of the the rest of the painting and that does cause problems because the wood will shrink differentially along the grain and across the grain so when you have something that's cross-grain it shrinks more across the grain and if it's locked from moving by having a cross-grain piece put against it it can often sort of like form splits and openings and we actually have got some damages along that edge where there is a very small sliver of a piece running across the grain. We've got splits that are actually opening up because of that piece so that's something that we also need to address. The first part of the conservation treatment of the reverse of the painting is to remove this filler that was put on as part of a repair treatment that was carried out because of a big split that happened because of the great frost. At that point the painting was treated structurally. These are very typical of repairs that have been done at the gallery in the early part of the 20th century. We see a lot of buttons and sort of repairs like this on the back of panel paintings. They're essentially a bit like sticking plasters where a panel has moved or there's been a split or a disjoin between boards and the boards have been reunited and then these buttons are put on to give some sort of like structural strength and stability. If a panel is well joined it doesn't tend to need these sorts of buttons and I'm finding that on this painting quite a lot of places where there are buttons actually the glue in that repair has failed anyway so many of these buttons I'm going to have to remove in order to carry out repairs. There are some buttons here that I've removed because there is a split across this part of the painting and you can see if you very gently flex the painting you can see that there is a line of movement along this crack which is it is an old damage but it's probably propagated and become worse so it's something that we need to repair and in order for me to be able to actually get glue into that I need to remove these buttons and that's that there are a few places that I'm going to have to do that. There's lots of bits of tape on the back of the panel where I've just been marking out where I can see that there are obvious places that the painting is moving this is a very obvious split here. Actually along this edge there is an addition that was put on probably when the painting was in Genoa in the 1800s it's a piece of timber that was put on across the grain of the painting and that means that the panel is more prone to split because of the the different orientation of the grain of the original boards and this little addition that's it's actually half lapped on so you can't really see it from the back and there's a similar addition down here but that's running in the same grain direction so it's not really such a problem but there are places along here this is why there are probably more damages along this edge than there are on the other edge so these these all need to be repaired. In a couple of places where I know that I have to do these repairs I've cut through the little piece of addition that's left so that I can actually move the painting make sure I can get the glue in and here the split is actually opened up against this this cross grain piece and so I have to take a small piece of that out so that I can actually close it up and we're just looking to see if it would be possible to remove that addition or not there are a lot of problems structurally with doing that and with the paint film on the front so I'm just looking at the best way as well of dealing with with that addition that has caused some problems in the past. So we're still really at the beginning of the structural treatment of this painting I just need to finish removing that filler from the corner there which means that we've got a much clearer view of everything on the reverse much easier to start looking more closely at the construction of the panel but also making sure that the repairs can be carried out. When we repair some of the splits we will have to turn the painting over so that we've got sight of the paint surface because we need to make sure that the levels of the front of the paint surface are aligned and we also want to look at the overall plane of the painting as well to make sure that that is consistent across the surface as much as possible and once we have carried out all of those repairs which are actually quite complicated on this because some of them are simply between parts of the campaign so there is a split along here in the centre of the panel that's quite hard to access but it's not insurmountable. Once we've done those repairs then we need to look at how the panel can be supported and that's that's quite complicated as well there are various options of what we can do in terms of a secondary support and we're still deciding what's the best option to use but it will need some form of secondary support because it's so thin for the size of it and for the fragility of the painting that we need to construct something for that as well and then at that point it'll go back to Larry again and he will do any filling and start the restoration of the paint surface.