Essential Information

Queen's House

12 Mar 2016

In preparation for the re-opening of the Queen's House some of our greatest treasures are being prepared for display. One of them has been waiting for attention in a dark corner of our stores for some time.

 Ceramics Conservator Tiago Oliveira and Preventive Conservator Liesa Brierley have joined efforts to bring this beautiful 17th Century Delft tile picture to a brighter life.
The tile picture before conservation
The Delft tile picture is made up of 113 tiles that were set into a heavy plaster backing re-enforced with wires and held within a steel frame. The resulting object was deemed too heavy to safely hang on the Queen’s House walls. Furthermore previous restorations had started to fail in some areas and a number of tiles were clearly set in the wrong orientation. In consultation with the tile expert Fi Jordan from the V&A it was decided to remove all tiles from the backing, conserve them individually and then reapply them to a lighter and more stable support for a safe display. 
Before starting the works samples of the plaster backing were analysed with the help of colleagues at the Natural History Museum to ensure safe working. 
Analyzing plaster samples
The analysis confirmed that the plaster contained sulphur and was therefore probably gypsum based. Gypsum cannot readily be dissolved or softened with water and mechanical removal was therefore required.  
Conservators don’t often take a chisel to an object. Read on to learn more about what it took to prepare this Delft tile picture for display
Each tile was carefully removed mechanically. Chisels and smaller blades were used when close to the ceramic and power-tools where the plaster was too stubborn. Whilst some tiles came off quite easily and whole, others had to be removed with a depth of plaster to prevent further damage.
Tile removal was easier where tiles had been broken in the past. Also note the stains from the rusted iron mesh in the plaster backing
Once all the tiles were separated, any remaining plaster was painstakingly removed from their backs
A steam cleaner was used to  further clean all break edges, glaze chips and larger losses a, which was very effective in removing ingrained dirt as well as residues from old plaster fills and paint
The backs of the tiles revealed some interesting information about the piece. It became obvious that at some point in the past the panel had been patched together from tiles originating from at least two different periods. The older type of tile was marked with an A and a number on the back. 
Markings applied to the back of the original tiles. All this information was carefully recorded and reviewed
Mapping of the different types of tiles and markings.
Preserved original tiles arranged according to the numbers on their backs using Adobe Photoshop
We have discovered that less than half of the original scheme has survived and that this scheme was wider and taller. To resize it to the current dimensions some full sized tiles had been cut or ground to half their size in the past. Replacement tiles had also been sourced to fill gaps. These appear to have been made specifically. It is also evident that some replacement tiles were already broken when the panel was assembled on the heavy plaster backing, suggesting that these have been removed from some other support before at least once.
Whilst large areas are missing or appear rather patched-up, the whaling scene is still readable as such. In the absence of good documentation of the complete original scheme it was decided to preserve the current appearance of the tile panel with only a few small changes, such as re-setting a few tiles that were obviously in the wrong orientation. 
In the next blog we will tell you all about re-assembling the tile picture and preparing it for display. 
We would like to thank Fi Jordan (V&A) for her professional advice and Dr. Tomasz Goral (Natural History Museum) for carrying out the analytical work on the plaster samples.
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