pose. Several other modifications can be made to the system, depending
onneed and limited only by imagination.Case description
The treatment of a large eighteenth-century panel^17 suggested another
rejoining method. The panel had been thinned. Rigid steel edge strips had
been screwed into the end-grain edges of the horizontal planks, preventing
movement of the panel across the grain during humidity changes. The
resulting constraint caused considerable disjoining, partly because of poor
environmental control.
The panel could have been treated horizontally, as in the case
described above. However, a more compact apparatus was used to provide
access and to make efficient use of studio space. Vertical orientation of
the painting is also advantageous because it allows easier access to both
sides than if the panel were oriented horizontally. Another benefit is that
some aspects of cleaning, filling, and retouching can be conducted in tan-
dem with the structural work if both sides of the panel are almost com-
pletely exposed.Apparatus description and application
Aframe/trolley constructed ofa metal girder with six wheels for mobility
was converted to a temporary support during treatment.^18 Apadded ledge
was affixed to the trolley bed, and the panel’s longest edge was laid onto it,
so that the panel planks were vertical with their backs facing outward.
Two silicone paper strips placed beneath the lower panel edge reduced
friction to allow warp movements. The topmost edge (a side edge of the
panel) was supported with a padded length ofgirder. Thus, the panel was
positioned for rejoining, back outward, as if on an easel.
Joining pressure was applied with polyester webbing straps fitted
with ratchet-uptake mechanisms. This type of strap, available in various
lengths, is typically used to tie down loads for haulage. The principle is
similar to that of a windlass-type tourniquet. Such tourniquets can be
manipulated to create a greater variety of pressure options than are pos-
sible with bar clamps.
Two straps(rather than one) were used. They were joined end to
end to encircle the panel—a method that achieved one line of pressure.
This method was used because the ratchet mechanism, if it were located
on only one side of the panel, would cause unequal tension on each side
because of friction at each end of the panel due to strap pressures. The
resulting constraint produces a bending pressure toward the uptake side.
However, when there is a ratchet on each side, pressure can be applied
equally or unequally, as desired.
The joining pressure of the straps was applied to the panel edges
through rigid end blocks, made from lengths of padded wood bolted into
girder lengths. At each end of the panel, a strap was run through a slot
in the girder and around the girder and the outside of the block. Each
ratchet was loosely suspended from such an end block, then positioned to
bear against the block when pressure was applied. Slings of cord or web-
bing were used to suspend the end blocks and ratchets from the top retain-
ing bar of the support frame, where the bar projected beyond the borders
ofthe painting. Thus the line of pressure could be directed at any desiredLarger Apparatus for
Treating Panels Vertically
S R M P P 429