The power of pure water

Water purification systems are relatively commonplace in a traditional laboratory setting, with a myriad of uses for pure water in a clinical environment. But take those into the ‘real world’, applied to complex and delicate practices such as museum conservation and restoration, and the true power of pure water is given stunning visual form

The Victoria & Albert (V&A) museum in London recently opened its doors to the public on its first ever exhibition of British quilts. Dating from 1700 to the present day, the 65 beautifully crafted quilts on show have been sourced from a variety of important collections, individual private owners, contemporary artists and the V&A’s own resource.

“Quilts are surprisingly rich and informative cultural artefacts,” explains Joanne Hackett, senior textile conservator, V&A. “The traditional style of quilting was designed to capture and document aspects of life, broader historical events, or personal and collective stories of a specific time. So it’s fair to say that the broad range of quilts we have on show during this exhibition describes a powerful cultural narrative that is really valuable for the V&A to explore.”

The range features bedcovers that commemorate the lives of prominent figures, such as Admiral Nelson, Charles II and the Duke of Wellington, and important events such as the coronation of Queen Victoria. Preparing such a diverse and precious collection for public display is an enormous undertaking, with some of the quilts in a much better state of repair than others that are hundreds of years old. It has taken six years for the exhibition to be ready for public view, from its initial conception, through to collation, restoration and final display.

“Many of the quilts and bedcovers required extensive cleaning before they were ready to exhibit, but this isn’t as simple as it might first sound,” says Hackett. “We can’t just pop them in the washing machine, as you might do with a quilt at home. If we subject any textile in our care to cleaning, our absolute first priority is to ensure the fabric is not distressed in any way whatsoever by the process. Museum cleaning is as much a process of restoration as it is an aesthetic one.”

The V&A uses the process of wet-cleaning for its most delicate and aged textile items. It is a time-consuming procedure, which is necessary to undertake by hand, and can sometimes last not just hours but even days. However, the museum conservators have found through experience that it is by far the most effective method for achieving a high standard of cleaning whilst preserving the integrity of the fabric.

Central to the effectiveness of the wet-cleaning process is the use of pure water. Hackett explains: “Without de-ionised water, the cleaning process just wouldn’t be possible. If we used normal tap water, even if it was treated, we would end up adding more chemicals than we would be trying to clean away.” In order to produce the de-ionised water, the textile conservation team uses a purification system from Purite, which has been supplying its specialist water purification systems to the museum from its Oxfordshire base since 1994. 

The Purite system used by the V&A team to clean the quilts for this exhibition

comprises a CC10 carbon filter and an NC10 ion exchanger. The unit itself has the capacity to process 6,000 litres of water at a time. This is enough to wet-clean approximately six normal sized quilts and reduces the amount of time the team needs to spend on refilling the system as they work through the collection.

One of the oldest quilts in the collection posed a considerable challenge to the textile conservation specialists preparing for the new show. First acquired by the V&A in 1937, and thought to have been produced in Wales sometime between 1800 and 1850, this quilted bedcover was made from a variety of block-printed and rolled printed cottons, measuring nearly 5m². “It was evident as soon as this quilt arrived at the conservation that it would need to be cleaned extensively before it would reach an acceptable display standard,” recalls Hackett. “We knew there were some vivid floral prints on this piece, so we really wanted to show it off in its full glory.”

The first stage in the wet-cleaning process is to lay out the quilt to soak in a 100 litre wash tank filled with de-ionised water. Once the quilt is thoroughly wet the water is carefully drained away and the quilt is then washed in a 2g/litre solution of Hostopan (an anionic surfactant) with 0.05g/litre of sodium carboxymethylcellulose (a soil suspension agent). This wash takes place at a room temperature of around 16 to 18°C. The quilt is then left to rest/soak for one hour before it is extensively rinsed in de-ionised water.

The wet-cleaning process can take up to six hours and each quilt may be subjected to several washes before the conservator is satisfied that the quilt is as clean as possible. The quilt is then ready to go through to the drying stage, which completes the cleaning and restoration process. During the drying stage, the quilt is laid flat on a table on top of a layer of unbleached cotton calico, and is then covered in a layer of cotton muslin. Fans are then arranged around the table to direct a stream of air over the surface of the quilt to aid evaporation.

The V&A museum has been using bespoke water purification systems which have been designed, manufactured, supplied and installed by Purite for the last fifteen years. Wet-cleaning using purified water has been a tried-and-trusted restoration method on numerous precious objects over this period of time. These have included 16th century chair covers, a Tudor heritage settee and an 8th century wall mosaic. It would not have been possible to clean items like these to such a high exhibition standard without the use of non-contaminating pure water.

“Although the wet-cleaning process can be time consuming it is also very rewarding to see an old quilt or piece of material literally ‘come to life’ as its original colours are revealed,” says Hackett. “The transformation of exhibits like the 200 year old quilt after the wet-cleaning process is a vivid visual demonstration of the real power of pure water.”