Relief Printing Process
In relief printing, we are talking about a matrix which can be inked and paper pressed against it, to produce an image. The ink sits on the surface of the matrix, and direct downwards pressure on the paper is applied, using either hand-rubbing or a press, to transfer the ink from the matrix to the paper.
In this way, ‘relief’ refers to the inked image standing in relief to the background on the block or plate.
In this post, I’ll be using a woodcut as the matrix to describe the relief printing process. The process of producing the actual matrix can be described in another post, as can pre-1600 methods and materials – for now, we are discussing the basic printing process. Some of the equipment used will be modern, as I gather and/or make their pre-16thC equivalents, but the basic process has remained the same since the early 15th Century.
It is worth nothing at this point, however, that to produce a woodcut, the plank, or grain, of the wood is used.
If the end-grain is used, this is called a wood engraving, and is not generally considered a pre-1600 Western European technique.
To begin the process, the block or plate being used should be clean from dirt, dust, oil, or anything else which would prevent an even coat of ink being applied.
There needs to be a flat, clean, smooth surface for the printing ink. Traditionally, relief ink is oil- (or for modern uses, can be plastic-) based. Water-based inks can dry too quickly on the matrix. A glass or marble slab is ideal, but any very smooth surface can be used. A portion of ink is set out on the slab and worked to ensure it is neither too stiff nor too soft, and that there is no dried ink or foreign matter present.
This would have been done primarily with a leather ink ball (as seen below), but here we are using a palette knife.
Above: ink balls, source –
An even layer of ink is applied to surface of the matrix. This is achieved through a number of thin coats (or passes) in varying directions, to achieve an even coating. In this demonstration, a roller is being used. The most usual method in period would have been to rock the ink on with an ink ball. Ink and paint rollers are generally regarded as being developed in the 19th Century.
If there is not enough ink on the matrix, the image will be insubstantial and patchy. If, however, there is too much ink, it can be forced down the sides of the cut edges, and be forced onto the paper when pressure is applied, creating a blurry line with thick, uneven areas of ink around the edges of the carved lines.
Here, you can see that there is enough ink to form a light ‘bead’ texture on the surface of the wood:
The matrix is placed on the bed of the press, or if is to be hand rubbed, in a clean area away from the inking area. A piece of clean paper, cut to a size to suit the image, is placed carefully on top.
If the image is to be hand-rubbed, any flat, firm utensil can be used on the back of the paper. A Japanese baren is an affordable, easy to use, modern choice, and gives good results. My own feeling is that something very similar would have been used in Western Europe before the development of the relief press in the 1440-50s, and that perhaps it was made from a disc of wood wrapped with leather.
The paper is used in the dry state (not dampened), and not too soft or flexible. This is so that the paper is not driven too far into the block as pressure is applied. If there is too much pressure, or the paper is too soft, one or several issues may occur. The crisp line of the cut image could be blurry, the paper could be damaged, or pick up ink which has accidentally gone into the background crevices, or even pick up the texture of the cut away areas. If the image is hand-rubbed, the paper must also be capable of withstanding that process, or be covered with another piece of paper, but this extra piece may move about and cause problems.
If the image is to be produced by means of a press, the paper and matrix are covered with a protective layer before being placed under the platen (the upper plate in a relief press which is lowered onto the matrix). This is to soften the direct impact of a large amount of force on the matrix.
This protective layer may be several/many layers of clean scrap paper, cardboard, woollen felt blanket, smooth rubber matting (a modern choice), a wooden backing board, or a combination of any of the above. Different combinations may alter the end result in a number of ways. A felt blanket directly above the paper, for example, will allow the paper to be pressed further into the matrix than a rubber mat or piece of cardboard.
Here, you see the matrix and paper covered with a rubber mat.
It is now ready for the bed to be rolled under the platen.
The platen is then lowered to make contact with the bed. The pressure forces most of the ink from the surface of the matrix onto the paper.
The process is then reversed – platen raised, bed rolled out, and any protective layer is carefully removed so as not to disturb the paper and matrix. Finally, the paper is removed from the matrix to reveal the image. It is hung, or placed on a rack to dry, usually for several days.
Sometimes, an impression of the force used to transfer the image can be seen in some way on the verso (reverse or back of print).
And so now finally, you can see the matrix and the resulting image, side by side: