reviously cut this process is apt to throw the leaves so far
out of their original position as to make them unduly uneven.

[Illustration: FIG. 7.]

Accurate folding is impossible if the "register" of the printing is
bad, that is to say, if the print on the back of a leaf does not lie
exactly over that on the front.

Crooked plates should usually be made straight by judicious trimming
of the margins. It is better to leave a plate short at tail or
fore-edge than to leave it out of square.

KNOCKING OUT JOINTS

The old "joints" must be knocked out of the sections of books that
have been previously backed. To do this, one or two sections at a time
are held firmly in the left hand, and well hammered on the
knocking-down iron fixed into the lying press. It is important that
the hammer face should fall exactly squarely upon the paper, or it may
cut pieces out. The knocking-down iron should be covered with a piece
of paper, and the hammer face must be perfectly clean, or the sheets
may be soiled.

CHAPTER III

Guarding--Throwing Out--Paring Paper--Soaking off India
Proofs--Mounting very Thin Paper--Splitting
Paper--Inlaying--Flattening Vellum

GUARDING

Guards are slips of thin paper or linen used for strengthening the
fold of leaves that are damaged, or for attaching plates or single
leaves.

Guards should be of good thin paper. That known as Whatman's Banknote
paper answers very well. An easy way to cut guards is shown in fig.
8. Two or three pieces of paper of the height of the required guards
are folded and pinned to the board by the right-hand corners. A series
of points are marked at the head and tail with dividers set to the
width desired for the guards, and with a knife guided by a
straight-edge, cuts joining the points are made right through the
paper, but not extending quite to either end. On a transverse cut
being made near the bottom, the guards are left attached by one end
only (see fig. 9), and can be torn off as wanted. This method prevents
the paper from slipping while it is being cut.

[Illustration: FIG. 8.]

[Illustration: FIG. 9.]

A mount cutter's knife (fig. 10) will be found to be a convenient form
of knife to use for cutting guards.

In using the knife and straight-edge a good deal of pressure should be
put on the straight-edge, and compa