29 July 2014

Conservation of a Ugandan shoulder harp at the Powell Cotton

A variation on the Egyptian New Kingdom shoulder harp, ennangas (arch harps) have for hundreds of years formed part of the rich musical heritage of Uganda. Used traditionally to accompany the singing voices of men, ennangas are recognisable by their elegant bowed neck, delicately laced strings, and falcate–shaped sound box which is usually covered by an animal skin.  Though often played at festivals and major ceremonies, the continuation of the ennanga as a “live” instrument was far from certain. With the loss of master and legendary harpists such as Temesewo Mukasa and the dearth of skilled musicians to instruct future generations, the musicologist Klaus Wachsmann declared in 1969 that the instrument was “practically extinct”. Gladly the ennanga has enjoyed a revival, you can see one in action here

Figure 1. Before conservation, strings broken.

Ugandan Ennanga (Walker Collection), Before Conservation
The Walker ennanga, collected over 100 years ago is comprised of wood, animal and reptile skins and vegetable fibres and is one of several in the Powell-CottonMuseum. The tautness of the stretched animal skin enveloping the top of wooden sound box and held in place by vegetable fibre lacing on its underside enables the sound box to still function as a resonator.  The vegetable fibres are integral: none are broken or friable. This is in part due to the ridges of stitched skin which encircles the mid-point of the sound box.  This ridge, formed by a series of running stitches from the laces being sewn into the leather, serves as a buffer as the tensile strength resides here and not on the individual laces.

The integrity of the sound box was in stark contrast to the condition of the strings at the neck of the instrument.  For whilst the neck shows soil marks and darkened patches from fingers on and between tuning pegs and the snake skin rings —all of which is valued as a biography of the object-- four out of the eight vegetable fibre strings were broken (Fig. 1). They dangled from the object’s neck and base.  Numerous attempts had been made over the years to repair the breaks. These attempts were not indigenous and resulted in various knots not only near the pegs but also at random sites along the fibre strings (Figure 2).     

Figure 2. Repositioning pegs with knotted vegetable fibre string. 

Knotting the strings had, in turn, resulted in an obvious shortening of their length and in heightening the tension which produced more breaks.  In counteracting the tension produced by the shortened strings, pegs had been repositioned and placed onto the other side of the neck.   Several knots were also anchored into peg holes, a short distance away from the indigenous knotting, as a makeshift measure to secure them into place.  The knots near  peg holes resulted in those pegs sitting crookedly in their slots due to their inability to be inserted completely. Several were at risk of falling from the neck.  There was also the problem of pegs being forcing into grooves which had knotted string.  This resulted in pegs becoming jammed.
         
Conservation

After cleaning non-indigenous accretions from the surface of the object, by brushing and with the use of a museum vac, the aims of the conservation treatment was to return the pegs to their original position (providing a structurally correct interpretation of the object) and to rejoin the broken strings.  The former of these was fairly straight forward and involved researching object descriptions, sourcing pictures and diagrams of ennangas, to ascertain how pegs should be laced and inserted into the neck. The rejoining of the strings proved more challenging, as gaps between the ends of strings ranged up to 10 cms.

At first, measures were taken to relax the knots through humidification (use of tyvek, blotting paper and deionised water beneath a micro-tent) in order to make the fibres suppler before unknotting and re-joining.  Unknotting was successful on two occasions and the unknotted fibres edges were consolidated at their ends before joining. No attempt was made to remove knot from strings if the strings were still integral. Their pegs were simply turned slightly to lessen the tension on the strings.

Figure 3. Inch gap between joins. 


With less than 5 cms square inches of mulberry paper and a small amount of wheat starch to create bridges between joins, a gap fill was created from conservation paper, adhesive, and nylon mono-filament: the nylon mono-filament serving as a substitute for the long fibres of the Japanese mulberry fibre as the conservation paper on its own had not the requisite strength.


Step 1: The filament was adhered to the paper with HMG. The end of filament was not covered with paper but left out to enable it to be joined with the consolidated ends of the vegetable strings.
Step 2:  Early stages of twisting paper. When dried the paper was twisted, at intervals, until it mirrored the twist of the string. 

Step 3: When the twist mirrored that of the string, the part of the filament which protrudes from the open end of the paper, was positioned on top of the vegetable string.  Conservation paper was then wrapped around both the string and filament and adhered into place by Poly vinyl alcohol.
Step 4: Lastly, a swatch of Japanese mulberry paper, that had been coloured to the shade of the string, was adhered around the join to secure it.  The paper was then crafted into mirror the twist of the vegetable fibre. 
The process was repeated on the remaining broken strings and these detachable gap fills were then coloured to resemble the strings.

Ugandan Ennanga (Walker Collection) after conservation. 


Novelette-Aldoni Stewart
Conservator, Powell-Cotton Museum. 

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