Plates of japanned tin or polished horn are proper for this purpose. Put pressing tins between the book and the millboards, up to the joint. Place one of the japanned tins on the side level with the groove, turn the book and japanned tin over carefully together, so that neither shifts; lay another of the japanned tins on the top of the book, thus leaving the book between 2 tins. Put the book into the standing press, screw down tightly, and leave for some hours. When pressed sufficiently, take the book out, and if the sides are polished, varnish them.
Make a little pad of cotton wool, saturate the lower portion with varnish; rub it on a piece of waste paper to equalise the varnish, then work the pad over the side as quickly as possible, in a circular direction. Renew the wool with varnish for the other side. Enough must be taken on the pad to varnish the whole side, as the delay of renewing the varnish would cause a streaked surface. When the varnish is perfectly dry, the book is again pressed. To do this, rub the gold-rag over the sides to give them a little grease, which will prevent the sides from sticking to the polished plates. Place the book between the plates as before, leaving out the pressing tins, and put into the standing press. Only little pressure must be given; if the press is screwed down too tightly, the plates will stick to the book. The varnish must be of good quality, and perfectly dry. Half an hour in the press will be found quite long enough. Should the plates stick, there is no other remedy than washing off the Tarnish with spirits of wine, and the glaire and size with warm water; then carefully re-preparing the whole surface as before.
This is, however, an accident which cannot happen if due care and judgment be exercised.