MACHINE USED FOR BLOCK PRINTING

Mechanization of block printing:
In 1834 a machine that automatically performed all the actions of block printing was invented by Perrot (it became known as the Perrotine), and achieved some success in block printing process. Mechanization block printing was limited to three dyes and a maximum repeat of only 15 cm and operation of the printing could not be truly continuous, but the three colours were printed simultaneously in that printer. Storey gives an illustrated account of this printing machine, and of hand block printing.

Much earlier, attempts had been made to obtain continuous surface printing using wooden rollers, but the difficulty of uniform application of the printing paste to the roller was the common problem. In about 1805, however, a rotating woollen fabric ‘sieve’ was introduced in Accrington, and used successfully thereafter. The other essential step of block printing was the preparation of a raised pattern on the roller by inserting copper outline strips and felt, just as in hand block printing. This technique of surface block printing was used until recently for printing furnishing fabrics and for wallpaper, but was never as important as the copper roller method. It had the advantages of requiring low pressure and avoiding the dyes contamination that occurs on engraved roller printing machines, because no contact was made with previously printed colour, but the cost of roller making of roller printing was high. Wallpaper printers found that inexpensive rollers could be cast from epoxy polymers and the nonprinting areas were easily cut away, but they did not carry enough colour to print most fabrics.

Essentially the same method of block printing has been used for printing polymer film, other packaging materials and transfer paper, but is then usually known as flexographic printing. The design is built up on wooden rollers by the application of rubber mouldings and the colour is applied by uniformly engraved metering rollers.

Surface printing machines with woolen fabric sieve

A Pressure bowl
B Surface roller
C Furnishing blanket moving over rollers 1, 2 and 3
D Colorant trough
E Plain furnishing roller rotating in colorant
F Second furnishing roller spreading colorant evenly on the blanket
G Blanket for extra resilience round the pressure bowl
H Back-grey
I Fabric to be printed
J Printed fabric

BLOCK PRINTING; SURFACE PRINTING METHODS

Block making for surface printing:
The typical hand block printing had no large, uniform areas of colour but was skillfully built up from many small coloured areas, because wooden surfaces larger than about 10 mm in width would not give an even print. Block printing had the advantage that a motif such as a flower would have an effect of light and shade obtained from three or four blocks, each block printing contains different depth of the same colour, or a different hue. This obviously meant that a lot of blocks were required. Special care was needed in setting the adjacent parts of the design during block printing. If the block printing design had a large repeat there would be a multiplication of the number of blocks because the size of a single block for block printing was limited to about 45 cm square and its weight to about 5 kg. Most blocks for block printing were much smaller than this, perhaps because many printers were women.

Wood blocks surface printing with brass strip and pin inserts

Block making for surface printing required patience and skill. A fairly hard wood was required, such as pearwood, and four or five layers were usually glued together with the grain running in different directions. The printing design was traced on to the surface and a fine chisel used to cut away the non printing areas to a depth of perhaps 1 cm. To obtain more detail from some blocks, strips and pins of copper or (more usually) brass were hammered into the wood. In the 19th century some blocks were made with the printing surface entirely in brass, which gave very delicate prints.
 

Wood blocks of surface printing with cast type-metal printing surface without pitch pins

 Another technique for surface printing used for complex printing designs was to prepare a mould, use this to cast the image from molten type metal, fasten the casting to the block, and then grind the surface perfectly flat. When large areas of solid colour were required, the areas within metal or wooden outlines were filled with felt, which would absorb and print the paste uniformly. Finally, each block required corner ‘pitch pins’ which printed small dots; these allowed the succeeding blocks to be correctly positioned by accurately locating the pitch pins above the already printed dots. A less precise form of block printing is practised in the production of, for example, Africa prints using large plywood blocks with polyurethane foam printing surfaces.
 

The printing table for surface printing:
A very solid table was needed; it was topped with flat surface slabs of stone or iron covered with a resilient blanket and a sheet of waterproof material for block printing. A back-grey of plain cotton was usually stretched over the table, to absorb any surplus colour for surface printing. Ideally the back-grey would be gummed to the table and the fabric to be printed could be pinned to it, for tight-fitting patterns.

The printing process of block printing:
Printing paste must be applied to the block surface in a controlled manner, and this was achieved by using a ‘sieve’. A small tub was nearly filled with a starch paste and a water proof fabric, stretched on a frame, rested on the block printing paste. A piece of woollen fabric was stretched on a slightly smaller frame and fastened to make the printing sieve. The sieve was saturated with printing paste and placed on the waterproof fabric. For each impression of block printing, the ‘tierer’ (a boy) spread the printing paste on the top surface of the woollen sieve with a large brush and the printer charged the block by pressing it on the wool. The block was then carefully positioned on the fabric, using the pitch pins as guides, and struck with a mallet. After printing a table length with the first block, the second was printed and then any others required completing the design. The fabric was then transferred to a few elevated surface printing rollers or rods and allowed to dry, while the next table length was printed.