Humidification!

Conservation of the bed hanging linings from the Spangled Bed continued throughout last year. Here’s an update from the National Trust textile conservation studio:

Humidification and wet cleaning

 Humidification of linings

The linings and satin were laid out inside a humidity tent created from a metal frame (a strawberry cage!) with a polythene sheet over to enclose the lining. A humidifier was set up inside to pump a fine water spray into the tent.

Lining relaxing in a humidity tent.

The linings were allowed to reach a humidity of 95% to allow them to relax. As the object was starting to relax glass weights were applied and it was then allowed to dry flat. Humidification resulted in the linings and satin to regain some of their lustre and body.

Wet cleaning of linings

After testing a variety of methods, detergents and buffer solutions, each piece of lining was washed in the wash table, pinned out flat and left to dry.

 An IMS : Acetone : Water (40:40:20) mix was used at the beginning of the wash to remove greasy soiling, followed by a wash bath with Dehypon LS54 (a conservation grade detergent) without a buffer and also with a buffer with a pH of 6.

The linings had an initial pH of 3.2 and was very acidic, so by introducing these different wash baths and using a buffer, which is a means of holding the pH at a steady level, we allowed the pH to be increased slowly.

Applying detergent and sponging the silk damask lining.  The lining sits on a mesh covered grid in the wash table to allow the wash and rinse solution to drain away, preventing it becoming too soft.

Applying detergent and sponging the silk damask lining. The lining sits on a mesh covered grid in the wash table to allow the wash and rinse solution to drain away, preventing it becoming too soft.

The soiling is very bound within the fibres, probably due to acidity, and proved difficult to remove through wet cleaning. Some dye loss also occurred although prior to cleaning it was noted that the ground of the silk was ‘cloudy’ where the dye had run from the crimson into the cream areas. This was probably due to the high humidity which, in combination with historic atmospheric pollution at Knole, had caused the silk to become more acidic and de-stabilised the dye. There is still some greyness to the object with striations of grey but overall the lining has improved immensely.

left to right – samples of water collected during wet cleaning process.

left to right – samples of water collected during wet cleaning process.

Removal of the silk damask and satin patches

It was decided to remove the patches to allow a more effective treatment of the satin.  Any necessary conservation treatment would have been worked through the patches causing damage and the patches would be lost as a future resource for research.

 The satin patches and the damask patches on the reverse of the satin were found to be adhered with starch paste. Damp blotting paper was placed over the patch and weighted in position. It was left for several hours allowing the glue to swell and soften. The patch could then be peeled away from the satin.

Humidifying the satin patch with dampened blotting paper.

Humidifying the satin patch with dampened blotting paper.

The patches were easy to remove and fortunately most of the adhesive came away with the patch and was not left on the curtains. The aim is to document and conserve most of the patches which will provide valuable information on some of the textiles used to furnish Knole or Copt Hall during the late 17th century.
Once the satin was humidified and the adhesive softened, the satin patch could be peeled from the surface (above) and the patch removal complete  . Once the satin was humidified and the adhesive softened, the satin patch could be peeled from the surface (above) and the patch removal complete

Once the satin was humidified and the adhesive softened, the satin patch could be peeled from the surface (above left) and the patch removal complete (above right).

Once the patches were removed, the satin curtain panels were humidified using the same method as for the damask linings.

 Adhesive treatment of the linings

Once washed, the damask linings had regained some of their handle and were less fragile. However they were much split and required an even, all-over support but could not withstand extensive stitching. An adhesive support was selected as the most appropriate treatment. Fine silk crepeline, a very fine gauze-like fabric, was dyed to match the damask and the crepeline was stretched out on polythene (which makes a backing film) and a 25% solution in soft water of Lascaux adhesive, (360HV and 498HV in a 2: 1 ratio) was applied with a small roller. This creates a fine adhesive backed fabric.

The damask panels were laid out and aligned and small ‘plasters’ of crepeline were used to hold distorted areas in place. Panels of adhesive crepeline were cut to shape and then applied using a roller system and laying the film evenly on to the reverse of the damask. The panels were turned face up and loose fragments were re-positioned.

Applying the adhesive coated silk crepeline to the reverse of the lining using the roller system.  The polythene backing is peeled away during the process.

Applying the adhesive coated silk crepeline to the reverse of the lining using the roller system. The polythene backing is peeled away during the process.

The adhesive film was then activated using a heat suction table and once cool the adhesive was set and the silk fixed to the support. Both linings had to be activated in two parts as they were too wide for the table.

Fixing the film to the lining on the right hand side, part of the two part activation.

Fixing the film to the lining on the right hand side, part of the two part activation.

The final stages of the treatment of the linings are to apply a dyed silk support to the reverse and dyed conservation net overlay using support stitching. This will take place once the proper right curtain linings have reached the same stage.

Note: All images © NT Textile Conservation Studio

 

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