Te Papa's Blog

We have had a very busy start to 2012, we have been working to have Poedua ready for display in March and preparing a number of paintings for the upcoming touring exhibition Angels and Aristocrats.

After the painting was re-stretched following the structural treatment, the old restorations including overpaint and old fills were removed.  The old fills and retouching were poorly matched to the original paint layer, in colour and texture, and in areas were broader than the damages, extending over areas of original paint.

A detail photograph of the old restorations over an old damage at the proper right inside elbow. Photograph taken by Melanie Carlisle, © Te Papa.

After the knowledge gained during the varnish removal and a number of further tests we determined that the only safe method for removing the old restorations was mechanically.  This involves very carefully scratching and chipping the additions away from the original layers.  This is done with small scalpels and dental tools under the stereo microscope.  It is very fine work and requires and strong and steady hand!

A detail of the same area as above after the old overpaint and fill material had been removed. The damage and loss to the original paint layer is revealed. Photograph taken by Melanie Carlisle, © Te Papa.

As you can imagine this is quite a time consuming process – each movement removing a barely perceptible amount, a square centimetre can take an hour or more.

Once all the old retouchings have been removed we can see the painting in its barest state – all that is left is the artists work and with the damages and deterioration exposed.  We record this with photographs before the next stage of restoration begins which involves adding to the painting to ensure the work reads according to the artist’s intent.

Overall image showing the complete clean - all surface dirt, varnish and old restorations have been removed. The damages and deterioration in the paint layer are exposed. Photograph taken by Melanie Carlisle, © Te Papa.

The first stage of restoration is the filling of the losses in the paint layer.  Many were revealed after the removal of the old restorations and the tiny pin hole loses caused by water damage in the lower centre of the painting were also filled.  We use commercial chalk based filler which has been tested and proven to have favourable ageing qualities, remaining reversible with time.

Overall image after the new fills have been added to the losses in the paint layer. Photograph taken by Melanie Carlisle, © Te Papa.

It is very important to emulate the paint layer texture in the fills and in the cause of this painting the texture is predominately the twill canvas texture showing through the very thin paint layer.  Under raking light we use small spatulas, scalpels and dental tools to create the required texture.

Detail of the same area as above after the new fill material has been added. Photograph taken by Melanie Carlisle, © Te Papa.

The painting is now ready for the first layer of varnish!

Come and hear about the conservation of the painting when Katherine and I present our work on Monday 5 March at Te Papa.  Find out more here.

Hello everyone, we are back with our fortnightly updates on the treatment of John Webber’s Poedua.

We are progressing slowing with the cleaning of the painting.  At this stage, the cleaning involves the varnish removal and the removal of overpaints (later additions by a previous restorer).

The painting on the easel in the Paintings Conservation lab. You can see some areas where the varnish has been removed; the sky to the right of Poedua's arm and square patches in the tapa cloth. Photograph taken by Melanie Carlisle, 2011. © Te Papa

Today’s blog post will focus on one stage of the cleaning – the removal of the paper label which was attached to the face of the painting down in the bottom right corner.  This label may have been attached for a sale or an exhibition that the painting was once in.  The paper label had been completely saturated with varnish, which made it resistant to the aqueous solutions that we would normally use on paper.  Using the same solvent solution we have been utilising for the varnish removal, we drew as much of the varnish out of the paper as possible and then applied a methyl cellulose gel to soften the paper label which allowed it to be removed.

During the removal process. This image shows the paper label coated with a layer of methyl cellulose. The Mylar on top ensures the methyl cellulose does not 'dry-up'. Photograph taken by Melanie Carlisle, 2011. © Te Papa

We discovered that there were actually two paper labels, as well as the remnants of another, one on top of the other, which we managed to separate during the removal process.  We took great care to remove the labels whilst keeping them as intact as possible.  The paper remnants were removed first which revealed the topmost label.

The topmost label once the paper remnants had been removed revealing 36. Photograph taken by Melanie Carlisle, 2011. © Te Papa

The topmost label suffered a few small tears during the removal while the lowest remains completely intact.  We cannot disregard this type of information which may assist in research into the provenance of the painting.  The numbers 8 and 36 may correspond with a lot number at a sale or a listing number in the catalogue for an exhibition.

Once the first label was removed, this label was revealed with the number 8. Photograph taken by Melanie Carlisle, 2011. © Te Papa

So no matter how small, information like this is very important and care must be taken to retain it.  It would have been easier to remove these labels in a method which destroyed the information, but if we are doing our job thoroughly it’s not about choosing the easiest methods or getting the fastest result!

In our last post we discussed the process of testing to identify the most appropriate cleaning solution to remove the surface dirt layer from the painting.

After finding the best cleaning solution for the painting the surface cleaning can begin, but we always carefully monitor our progress to ensure that the cleaning solution is working effectively without any adverse effects for the painting.

We generally begin in the lighter areas of the composition, because we can see the progress best in these areas and it allows us to get a feel for the action of our cleaning solution.  We hand-roll cotton wool swabs on bamboo sticks and slightly dampen the swabs with the cleaning solution.  The damp swabs are rolled across the surface of the painting and the dirt is lifted and removed from the surface.  We stop rolling the swab once it appears dirty.  We don’t want to roll the dirty swab across the surface because the particles which collect on the swab may be abrasive.  Because this painting is so dirty we had to change our swabs quite regularly!

Here are some nice photos to show you the progress of the surface clean.  You can see the difference that removing this layer has on the colours, tone and depth in the painting.

We begin by expanding our test areas. This rectangle is the first area of the painting to be cleaned. Photograph taken by Melanie Carlisle. © Te Papa.

We continue by expanding the rectangle. The removal of the surface dirt layer is revealing the depth in the composition. Photograph taken by Melanie Carlisle, 2011. © Te Papa

The cotton wool swabs are changed after a few rolls across the surface. We filled three jars of swabs completing this treatment. Photograph by Melanie Carlisle, 2011. © Te Papa

Katherine and I working on the painting. Photograph taken by James Kirk, 2011. © Te Papa.

Cleaning progressed from right to left. In this detail the difference between the dirty and the cleaned sections is distinct. Photograph taken by Katherine Campbell, 2011. © Te Papa.

The cleaning is almost there! The top left of this detail is all that remains of the surface dirt layer. Photograph taken by Melanie Carlisle, 2011. © Te Papa.

Katherine works cleaning the top left corner. Photograph taken by Melanie Carlisle, 2011. © Te Papa.

The painting after the surface cleaning. The varnish layer still hides the true colours and tones, but already we see a great improvement. Photograph by Melanie Carlisle, 2011. © Te Papa.

There has been a significant change in the appearance of the painting and Poedua is looking much better already!  The removal of the surface dirt layer has revealed the varnish layer beneath it.  The varnish is yellow, discoloured and uneven.  The next stage of the treatment is to remove this varnish layer.  This is the most complicated stage of the treatment.

Poedua (Poetua), daughter of Oreo, chief of Ulaietea, one of the Society Isles, 1785, Webber, John (1750–1793). Purchased 2010. Te Papa

Welcome to the first blog to keep you up-to-date with the conservation treatment of John Webber’s portrait of Poedua.  Katherine Campbell and I, the two paintings conservators here at Te Papa, will aim to post fortnightly on the progress of our work, offering you insight into what happens to a painting during a conservation treatment.

The painting arrived in the paintings conservation lab shortly after being taken down from display in Toi Te Papa.  Our first task was to remove the painting from the frame and to remove the temporary backing board which had been attached to the reverse of the painting for the transit from London to Wellington.  This is done in order to gain unimpeded access to the whole work, from the front and back of the canvas.

Katherine examining the painting with a hand-held microscope, 2011, Photograph by Melanie Carlisle. © Te Papa

One of the most important aspects of a conservator’s job is documentation; we need to clearly record the current state of the artwork or object.  For a painting, this documentation is generally broken down for each of the paintings ‘layers’.  We begin at the auxiliary support (in this case the wooden stretcher), the primary support (the twill canvas), the ground layer (or priming, preparatory layer), the paint layer and the surface coating.

This report includes a detailed description of the layers, covering visual appearance and the artist’s technique; we also consider what materials were available to the artist and often reference colourmen’s catalogues from the time and place the painting was executed.  We also document the current condition of each layer, with possible reasons behind that condition and any ongoing issues of deterioration.   

It is this documentation that we have been working on for the past few weeks which will help inform us about what treatments to undertake.  We use a variety of different technical examination techniques to aid us in finding out as much as possible about the painting. 

Some of these techniques include examining the painting with different forms of illumination; using normal lighting sources, we look at the painting in reflected, raking and transmitted light.  We use UV lamps in a dark room to investigate the surface coating and any later additions by a previous restorer.  We use infrared photography to see through the paint layer and identify (if they are present) preparatory drawings as well as artists changes (pentimenti), damages and associated restorations.  We examine the individual brushstrokes using a stereo-microscope and get to know all the fine details in the painting.  We use these photographic images to help illustrate and complement the written condition report.

Infrared photograph - detail, 2011, Photograph by Michael Hall. MA_I227737. © Te Papa. The small red circle at the bottom shows the changes the artist made to the scale of Poedua's little finger (pentimenti). The larger red oval shows an area where the paint layer has been damaged and covered with a previous restorers overpaint.

Ultra-violet photograph of Poedua, 2011, Photograph by Melanie Carlisle © Te Papa - This image shows the auto-fluorescence of the natural resin of the varnish when exposed to ultra-violet light. The brushstrokes from the varnish application can be seen. The variation in the auto-fluorescence indicates the uneveness of the varnish layer.

Once this stage of the documentation is complete, we write a treatment proposal to outline what we hope to achieve with our conservation treatment.  The technical examination continues throughout the conservation process, we continue to learn more about the painting and the artist as we spend more time with the painting.