Fig. 65--Appliances used in blocking backs.
To enable the most various widths of backs to be quickly inserted and to supply a substitute for the thick layers of cardboard packing which make a fine impression impossible, a special contrivance with metal pads has been made. This is shown in the sketch herewith.
Mention has already been made of the table (or matrix). This is a bed of stout boards which is intended to serve the double purpose of saving the blocks when blocking thin articles (backs of covers, &c.) and also for strengthening and equalising the resistance from below when working on heavier articles. Faults arising during working, such as insufficient adhesion of the gold (and an increased pressure) may be set right by pasting on pieces of paper to the matrix or table.
The matrices consist of strong but thin material; the best is wrappers or the thinnest board. After use they are kept for subsequent repetitions of the same or for other work.
The lettering must always be set up fresh for each job, whilst the ornamental pieces may be arranged on the tables or matrices at hand after the existing original impression.
Setting the type is a special art and calls for considerable taste and skill; the letters very easily slip out of the type-holder, especially where very small type is used, unless special precautions are taken to prevent this. Here we will pass over the most important point in the arrangement of the types and refer to the paragraph dealing with "Lettering" under "Hand-tooling"; what holds good there always holds good here.
Lettering is always set upon special pieces of board and afterwards encased in a type-holder, as it demands much more attention and subsequent correction. These boards should likewise be wrappers of the same thickness as those used at the same time for the ornaments. For fixing, cobblers' wax is likewise used. The favourite method frequently adopted of using glue coated with paste is not to be recommended, because the letters do not admit of proper setting upon this gelatinous mass. Not only do the lines of letters require to be kept right by means of a strip of metal or metal line, they must be carefully adjusted after taking a light impression, especially when using a very small type. The first pull must be under so light a pressure that on a soft paper everything is distinctly visible. The lines are arranged from this proof, whilst each single letter is carefully checked. Where letters do not show up properly they must be backed up with paper of suitable thickness on the board until all unevenness disappears. The lighter the pressure applied the easier it will be to make corrections. Letters heavily pressed at the outset can seldom be properly rectified afterwards.