The heart of hand block prints lies in the wooden blocks created for the purpose.
Woodblocks for textile printing are made of box, lime, holly, sycamore, plane or pear wood, the latter three being most generally employed. They vary in size considerably, but are mostly between two and three inches thick, otherwise they are liable to warping. Warping is additionally guarded against by backing the wood chosen with two or more pieces of cheaper wood, such as deal or pine.
The several pieces or blocks are tongued and grooved to fit each other, and are then securely glued together, under pressure, into one solid block with the grain of each alternate piece running in a different direction. The block, being planned is quite smooth and perfectly flat.
Next the design is drawn upon, or transferred to it. This latter is effected by rubbing off, upon its flat surface, a tracing in lamp black and oil, of the outlines of the masses of the design. The portions to be left in relief are then tinted, between their outlines, by ammoniacal carmine or magenta, for the purpose of distinguishing them from those portions that have to be cut away.
As a separate block is required for each distinct colour in the design, a separate tracing must be made of each and transferred (or put on as it a termed) to its own special block. Having thus received a tracing of the pattern, the block is thoroughly damped and kept in this condition by being covered with wet cloths during the whole process of cutting. The block cutter commences by carving out the wood around the heavier masses first, leaving the finer and more delicate work until the last so as to avoid any risk of injuring it during the cutting of the coarser parts.
When large masses of colour occur in a pattern, the corresponding parts on the block are usually cut in outline, the object being filled in between the outlines with felt, which not only absorbs the colour better, but gives a much more even impression than it is possible to obtain with a large surface of wood. When finished, the block presents the appearance of flat relief carving, the design standing out like letterpress type.
Fine details are very difficult to cut in wood, and, even when successfully cut, wear down very rapidly or break off in printing. They are therefore almost invariably built up in strips of brass or copper, bent to shape and driven edgewise into the flat surface of the block. This method is known as coppering, and by its means many delicate little forms, such as stars, rosettes and fine spots can be printed, which would otherwise be quite impossible to produce by hand or machine block printing.
Frequently, too, the process of coppering is used for the purpose of making a mold, from which an entire block can be made and duplicated as often as desired, by casting. In this case the metal strips are driven to a predetermined depth into the face of a piece of lime-wood cut across the grain, and, when the whole design is completed in this way, the block is placed, metal face downwards in a tray of molten type-metal or solder, which transmits sufficient heat to the inserted portions of the strips of copper to enable them to carbonize the wood immediately in contact with them and, at the same time, firmly attaches itself to the outstanding portions.
When cold, a slight tap with a hammer on the back of the lime wood block easily detaches the cake of the type-metal or alloy and along with it, of course, the strips of copper to which it is firmly soldered, leaving a matrix, or mold, in wood of the original design.
The casting is made in an alloy of low melting-point, anti, after cooling, is filed or ground until all its projections are of the same height and perfectly smooth, after which it is screwed onto a wooden support and is ready for printing. Similar molds are also made by burning out the lines of the pattern with a red-hot steel punch, capable of being raised or lowered at will, and under which the block is moved about by hand along the lines of the pattern.
They are two to three inches thick, of different sizes and re-inforced by two or more wood pieces of deal or pine. The fabric for the prints is laid out on flat tables and the hand block printing done.
Earlier dyes used were natural and vegetable colours. But today with synthetic dyes easily available, much cheaper comparatively and easy in usage, they are widely preferred.
Very small detailing can be etched and preserved in the block by special provisions. So small stars and very minute designs otherwise not possible, are available for the beautification of the fabric. Flowers, fruits, trees, birds, geometrical designs and figurative patterns are some of the popular motifs in block printed sarees.