Since covering the edges with the window mat would
probably cause a disturbance of the image,as the
mat would abraid the surface of the drawing, its
edges will have to be exposed. This means that
the skin will have to be hinged in a manor that
will keep it as flat a possible. Hinges can be
placed on all of its edges and passed through the
back mat, so that they can be pulled out onto the
back side of the back mat. It is also possible to
attach only the feathers of strips of wet-cut Japanese tissue so that they are attached to all
of the edge of the skin. These strips can be pasted to their neighbors, at their ends and they
can be allowed to show, between the edges of the
drawing and the edges of the window, so that the
window will hold down the tissue and thereby, it
will restrain the edges of the skin.
In either case, desiccated blotter should be used
to hand dry the hinges to avoid cockling in the
vellum.
Hugh