Tapestry conservation is a long process – from the initial estimate and bids for funding to the final redisplay can take many years.
We are on the final leg of the Powis Castle ‘Reception of an Embassy’ tapestry and I thought I would share with you our bulletin updates to the property. These give you an insight into some of the work that has been completed and the challenges we have faced.
For ease of estimating at the Studio we have made a grid which we can lay onto the tapestry which marks the tapestry into 20cm sections. In this way we can judge the level of damage in each section and make an estimate of how long the conservation will take based on previous tapestries worked on with similar levels of damage. In photograph 1 a conservator can be seen laying the grid over the tapestry as it lies on the ballroom floor. Initially the tapestry was surveyed and an estimate for its conservation prepared whilst it was still on display at Powis Castle.
The tapestry was delivered to the Textile Studio in May 2013. Our first task was to record the condition of the tapestry before any treatment and have a professional photographs taken.
This tapestry has several problems as it has been worked on extensively in the past. At some point during its history it has been cut into four quarters with a horizontal and a vertical cut. The top left-hand quarter is considerably more soiled than the rest of the tapestry with general overall soiling and harsh tide marks from water staining. These four quarters have since been re-joined and the tapestry was displayed as a complete hanging.
One problem that tapestries commonly suffer from is the loss of the dark brown wool wefts. This is due to the iron salts which were used to mordant (fix) the dyes, these iron salts speed up the degradation process of the wool making it brittle and prone to loss. There has been extensive loss of the dark brown weft in this tapestry which has been replaced by re-weaving. On the whole, when viewed from a distance this re-weaving is not visually disturbing and is sound and will therefore be left in place. In some areas it has been rather crudely executed and appears rather heavy-handed; in these areas it will be removed and replaced with closely spaced couching over alternate warps to support the tapestry and give a more sympathetic colour in-fill.
Before the tapestry can be given its stitched support it needs to be washed. There were several challenges involved with washing this piece. One was to remove the heavier soiling and staining from the top left hand corner so that the whole tapestry has a more harmonious appearance and the second is all the re-weaving in the dark brown wool weft, very often the dyes in the re-weaving prove to be fugitive during wet cleaning.
In preparation for wet cleaned the heavy linen/hessian lining has to be stripped off. A lot of the previous repairs had been worked through this lining so they had to be cut in order to release the lining. The vertical and horizontal joins where left stitched together and the lining cut back.
The dyes used in the original are generally fast during washing although later repairs can be fugitive. Samples of all the wool yarns used in the re-weaving were tested and these all proved to be wet fast although a dark navy linen thread used extensively to re-stitch slits bled dye when tested. It was therefore necessary to remove this thread before wet cleaning.
The Studio has a long standing relationship with a workshop in Mechelen, Belgium which has a specialised wet cleaning facility. The unique features of this facility are that the tapestry can lie flat on a perforated metal base, through which an aerosol of water and detergent can be sucked. This is normally sufficient to release the soiling but with more heavily soiled tapestries additional sponging by hand is carried out.
Due to the specific issues with wet cleaning this tapestry the Textile Conservator went over to Mechelen to oversee the wet cleaning; in consultation with the Director of the workshop it was decided to wash the tapestry at a slightly lower pH as this would inhibit any potential dye bleeding of the repair threads. During the wash process the top left hand corner was give extra sponging and soft brushes were used to reduce the soiling and staining.
The results of the wet cleaning were very successful, although it was not possible to remove the staining completely it is very much reduced and the appearance of the whole tapestry is much more harmonious.
Following the wet cleaning in Mechelen the tapestry was transported back to the Studio for the stitched conservation.
Continuing on from an earlier post about the conservation work we undertook on the Reception of an Embassy tapestry from Powis Castle here is the second in a series of bulletins we sent to the property. This post dates from October 2013.
While the tapestry is at the De Wit workshops for wet cleaning there is also the opportunity to take high resolution photographs of the front and reverse after wet cleaning using the workshop’s photographic studio.
The contrast between the faded front and the original colours on the reverse enables one to imagine how rich and colourful the tapestry would have been when first woven. Unfortunately there is nothing that can be done to restore the original colours as the dye molecules have been permanently altered by exposure to light. This is why the National Trust limits the levels of light to which their sensitive collections are exposed.
What the wet cleaning has been able to do is to lessen the harsh staining and make the whole tapestry visually more harmonious. Before cleaning, the upper left-hand quarter was significantly more soiled and stained than the rest of the tapestry.
The conservation treatment will involve applying a backing of linen scrim to the reverse of the tapestry and the conservation stitching, which will support and re-integrate missing areas of design, is carried out through this linen backing.
Once the cleaned tapestry was delivered back to the Studio it was mounted onto a wooden frame with three rollers to allow the attachment of the linen support. The linen support is rolled on the middle roller and is attached to the tapestry every 21cm across its width.
For estimating purposes the tapestry was marked into 21cm sections. As we work through the tapestry we can keep track of the actual time taken versus the estimated time.
During the weaving process where there is a change in colour and to create design features, slits are formed in the weaving. These are originally stitched together using linen threads. Over time this linen thread degrades and fails. In some areas the linen slit stitches have been replaced with crude stitching in unsympathetic colours. Where the slit stitches are original they are reinforced by stitching over them with a cotton covered polyester thread. Where there are unsightly repairs these are removed and replaced with the cotton covered polyester thread in a toning colour.
Before starting work on the tapestry it was necessary to dye some yarns. Wherever possible we will use commercially dyed yarns if the colour and the light fastness are suitable, however, one supplier has stopped producing one of the yarns that we used to use. Sometimes it is just not possible to find the correct colour and thickness so yarns have to be specially dyed in house.
In the Studio we use Ciba Giegy chemical dyes, even though the dyes used in the original tapestry are natural dyes. The reason for this is that the original natural dyes have already done the majority of their fading, as can be seen from the comparison of the front and the reverse, and we will match the faded colour with a stable chemical dye. If we were to use natural dyes for the repair yarns these would fade and more rapidly than the original faded natural dyes and cease to blend in.
As mentioned previously the dark brown wool weft is particularly vulnerable to degradation due to the iron salts used to mordant the dye. As a consequence large areas of the dark brown wool are missing and sparse. Some of the missing areas have been rewoven. This has been done rather crudely and with an unsympathetic yarn which, when a fibre sample was examined under the microscope was found to be acrylic. As this reweaving is so extensive it will not be possible to remove all of it, but discrete areas where it is practical will be removed and replaced with brick couching over the warps in dark brown wool. The photographs below show one of the faces where the definition has been re-introduced by couching in the pupils of the eyes and other features and some of the especially crude re-weaving in his hat has been removed and replaced.
In areas where the silk weft is missing or weak we couch the exposed warps using commercially available stranded cottons. The cotton has a lustre that is comparable with that of aged silk and it is available in a wide range of colours that can be blended to match the subtleties of the original silk weft.
The conservation stitching is progressing well and we are almost a quarter of the way through the tapestry.
Continuing on from earlier posts about the conservation work we undertook on the Reception of an Embassy tapestry from Powis Castle here is the third in a series of bulletins we sent to the property. This bulletin dates from January 2014.
The tapestry is mounted onto a frame and stitched onto a support of linen scrim. The conservation stitching provides a combination of strength and support by evenly attaching the tapestry to the linen support fabric and an aesthetic reintegration of missing areas of design.
An area of previous crude repair which was unpicked, new warps were inserted and then couched down with coloured wools to match the missing wefts. By removing these visually distracting repairs the original weaving can be read more readily.
The shoulder and face of this figure have had a previous repair which has been crudely executed in unsympathetic yarns and colours. The repair was removed, new warps were inserted across the hole, then couched down through to the linen support fabric with wool and stranded cottons in the correct colours. This conservation stitching gives a more accurate impression of the original design. The aim with tapestry conservation is that when the tapestry is viewed overall the original design should be harmonious and able to be read, but when the tapestry is viewed close to it should be possible to see which elements of the weaving are original and those that are repairs. The spaced couching over one warp and under the next uses the same principle as the original weaving, but is carried out through a support fabric so that it is possible to easily identify it as a repair.
The work on the tapestry is progressing well and we have completed ten out of 26 sections. As well as dealing with the inherent weaknesses in the tapestry, for example failing horizontal slits and degrading dark brown wool and cream silk at some point in its history the tapestry has been cut up into quarters and then re-joined. The top left hand quarter has obviously been exposed to more agents of deterioration during its life as it has several bleached stains and completely missing areas. It is not known what has caused this damage, but in the bleached areas the wool warps and weft are very brittle and there are completely missing areas. In some of the missing areas it is not possible to know exactly was the missing design was so the decision was made to in-fill the hole with a dyed fabric patch. A specially woven ribbed fabric was used to imitate the tapestry weave to give the correct texture.
The next few sections of tapestry that we are moving onto are less damaged and their conservation will be more straight-forward; before we face the challenge of the vertical cut that runs the whole width of the tapestry.
Continuing on from earlier posts about the conservation work we undertook on the Reception of an Embassy tapestry from Powis Castle here is the fourth in a series of bulletins we sent to the property. This bulletin dates from June 2014.
The relative silence from the Studio has been due to us tackling the challenging vertical cut that ran through the whole length of the tapestry. This cut had been crudely re-stitched and was coming apart so conservation was necessary for aesthetic and structural reasons.
I have just calculated that based on 5½ warps per cm and a total height of 370cm that we inserted over 2,000 warps. This section took us 360 hours to stitch, by far the longest in the whole tapestry.
All the new warps inserted across the long vertical cut which runs the full height of the tapestry.
Once all the new warps were in place we could begin to stitch them in place with brick couching in stranded cottons and wools to match the missing weft. In some areas there was loose original weft still remaining. In these areas the warps were woven in and out of the weft to mimic the original weaving technique.
Detail showing the failed stitching along the vertical cut.
Detail showing the warps inserted across the vertical cut.
The vertical cut went through the Latin inscription ‘EX FERRO/FI(V)NT/QVE/DVRATVRA/PER EVVM’, which translates as ‘out of iron come things that will last forever’, on the banner over the striped doorway and a letter was missing. This was the letter ‘V’ in FIVNT. In order to replace the letter a tracing was taken of another letter ‘V’ in the inscription onto Melinex®, a clear polyester sheet. This tracing was used to determine the positioning of the couching stitches that would make up the missing letter.
New warps have been inserted across the vertical cut and a tracing of existing letters made to fill in the missing letters.
Part way through couching with cream and dark brown wool to recreate the missing letters. The missing letters filled in.
The other major challenge that we have faced in the second half of the tapestry has been some of the crude re-weaving that has been carried out in the dark brown wool areas.
The dark brown wool weft is particularly vulnerable to degradation due to the iron salts that were used to mordant (fix) the dyes originally. These iron salts accelerate the degradation of the wool fibres with the result that the dark brown wools are often lost.
In the Powis tapestry the re-weaving has been crudely executed in a yarn which is black rather than dark brown to match the original. A small sample of the re-weaving yarn was taken from the reverse of the tapestry and examined under a microscope to determine what type of fibre it was – it proved to be 100% acrylic! Having said this the re-weaving was very extensive, so in areas where it had been reasonably well executed the decision was made to leave it in place, blending in any further weak areas with new brick couching in wool. In the areas where it was very crude, causing distortions and the black colour was visually disturbing the decision was made to remove it. The decision as to which areas to leave and which to remove was made at the outset of the treatment with the whole tapestry laid out so that specific areas could be examined against the overall effect.
The striped archway once the crude acrylic re-weaving had been removed and replaced with dark brown wool brick couching.
The final five sections of the tapestry are in better condition, so we are feeling like we are on the homeward straight now. The next job is to order the weaving of some new brown galloons with which to edge the tapestry. When the tapestry was taken down for conservation it had a blue linen fabric edging all four sides, when this was removed the original dark brown galloons were revealed on the two side edges. The decision was made to have new galloons woven for all four sides to give a crisp outline to the whole tapestry. The original side galloons will be protected beneath the new replacement ones.
The tapestry will then be lined with down proof cotton cambric to protect the conservation stitching and to reduce the movement of air through the tapestry and consequently the soiling. We currently propose to re-use the popper tape to re-hang the tapestry from as it is in good condition.
If you are in the area, please do go and take a look or if you would like to know a bit more about this tapestry take a look at The National Trust’s Collections online information here.