er, with a
straight-edge and folder. In panelling a back, the side lines of all
the panels should be marked in at the same time with a folder, working
against the straight-edge, held firmly at the side of the back. If the
panels are worked separately, it is difficult to get the side lines
squarely above each other. The lines at the top and bottom of the
panel may be marked in with a folder, guided by a piece of stiff
vellum held squarely across the back. If there are lines to be run
round the board, they can be marked in with a pair of dividers guided
by the edge of the board, except those at the back. These must be
measured from the fore-edge of the board and run in with straight-edge
and folder.

When straight lines occur in patterns that are blinded through the
paper, it will be enough if the ends only are marked through with a
small piece of straight line, and the lines completed with
straight-edge and folder, after the paper has been removed.

Unless the finisher has had considerable experience, it is best to
deepen all folder lines by going over them in blind with a fillet or
piece of straight line.

When the pattern has been worked in blind, either through a paper
pattern or directly on to the leather with the tools, and any inlays
stuck on (see page 213), the cover should be well washed with clean
water. Some finishers prefer to use common vinegar or diluted acetic
acid for washing up books. If vinegar is used it must be of the best
quality, and must not contain any sulphuric acid. Cheap, crude vinegar
is certain to be injurious to the leather. Porous leather, such as
calf or sheep skin, will need to be washed over with paste-water, and
then sized.

Paste-water is paste and water well beaten up to form a milky liquid,
and is applied to the leather as evenly as possible with a sponge.
When the paste-water is dry, the leather should be washed with size.
Size can be made by boiling down vellum cuttings, or by dissolving
gelatine or isinglass in warm water.

For the less porous leathers, such as morocco, seal, or pig skin, no
paste-water or size is necessary, unless the skin happens to be a
specially open one, or the cover has been cut from the flank or belly.
Then it is best to put a little paste in the vinegar or water used for
washing up. When the leather is nearly, but not quite, dry the
impressions of the tools must be painted with glaire. Finishers'
glaire may be made from the white of eggs well beaten