Aquatint is an intaglio technique used to produce tonal effects rather than lines. A metal plate is coated and fused with a fine rosin powder and any white areas in the image are blocked out using Stop Out varnish. The plate is then put in to the etchant for the required time to produce the palest grey. The palest grey is then blocked out, the plate etched again and so on until the darkest tone has been achieved.
Drypoint etching is an intaglio form of printmaking. A drypoint needle is used to scratch an image onto a metal or plastic plate and ink is pushed into the grooves created by the needle. Drypoint relies not only on the groove provided by the needle but on the burr of material made when scratching the surface. This gives it a line with a velvety fluctuating character.
Etching is an intaglio process - intaglio coming from the Italian word intagliare meaning to “incise”. In etching a metal plate is coated with hard or soft wax and marks are made into this using a sharp tool to expose the metal beneath. The plate is placed into etchant which eats in to the exposed metal. Ink is then pushed into these etched marks which when passed under a press creates the print.
Letterpress printing was invented by Johannes Gutenberg in the mid-15th contrary and is a relief printing technique using wood or metal type. The type is composed in a “chase” to create the desired text, inked up and paper pressed against it to transfer the ink from the type onto the paper.
Linocut is a relief printing process in which the lino is cut away with gouges to leave an image on the remaining raised areas and it is this which is then printed. More complicated and multi-coloured images can be achieved through the use of paper stencils, the Reduction method or with Multiple plates.
Lithography is based upon the fact that grease and water do not mix. In stone lithography images are drawn on the stone surface using materials containing grease. Using a solution of nitric acid and gum arabic causes a chemical change in the surface of the stone, this then creates areas which attract ink and repel water.
In photolithography, images are made on drafting film or printed digitally on to acetate. The plate is then exposed to UV light and developed to create areas which attract ink and repel water. Polyester plate lithography uses special hydrophilic plates which can be drawn on or printed with a laser printer.
Screen printing is also called Silk Screen. It uses a wooden or aluminium frame which has fabric, originally silk now a synthetic material, stretched over it. It is a stencil based process: a stencil is attached to the screen and when ink is pushed through the mesh an image is created. Stencils can be made from paper, drawing fluid, screen filler or photo emulsion.
Developed in the 1970s, this technique is an etching process which uses a metal plate coated in a light sensitive polymer film. Both photographic and drawn images along with actual objects can be placed on to the plate which is then exposed to a UV light source and developed in water. This process captures very fine detail and can be used to produce both intaglio and relief printing plates.
A form of relief printmaking, a Woodcut image is created when the side grain of a piece of wood is cut away to leave an image on the remaining raised areas and it is this which is then printed. The marks are much coarser than with wood engraving, with the character of the wood being visible and a part of the final image.
Wood Engraving is a relief printing process known for its small scale and detailed fine line work. A tool called a graver is used to cut the image into the polished surface of the end-grain of a hard wood block. Ink is applied to the surface of the block but the engraved lines do not receive the ink - being below its surface - and so come out as white on the printed image.