The conservation of Poedua – part 1

The conservation of Poedua – part 1

Poedua [Poetua], daughter of Oreo, chief of Ulaietea, one of the Society Isles, 1785, by John Webber. Purchased 2010. Te Papa (2010-0029-1)

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.


  1. Thanks for hooking me into the blog Katherine. How fascinating. I will follow the progress. Such a great idea to do this for those interested in following the progress.

  2. Wow the csi of painting! This is absolutely fascinating

  3. Oh that’s amazing to see your various analyses. So thorough, I’m never going to paint again for all the pentimenti I’ll execute – madonna!

  4. Brilliant work ladies! Hello to everyone in the lab! I miss you all!

  5. Well done ladies, very comprehensive article, even for the ‘uninitiated people’.
    Will be looking forward to follow your progress.

    bon courage mesdames!

  6. wow – that is fascinating; thanks for the post and happy conserving!

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