Aquatint
This is a form of etching. A plate upon which an image has been incised is then covered with many tiny particles of rosin (a form of resin) which stick to the plate through heating. The plate is then immersed in the acid again, and the rosin allows the acid to bite through evenly, creating areas of tone on top of the incised lines. These areas mean that aquatints can often look like ink-brushed drawings or watercolours.

Collagraph
From the Italian "collare" meaning to stick with glue, this is a form of relief printing in which a design is built up on a printing block by sticking things onto it. The raised areas of the block then are covered with ink and the print taken. See also woodcut.

Crayon Manner
A method of intaglio printing that reproduces the effect of pencil and chalk sketching on the finished print. This is achieved by taking a print from a "ground" (wax) covered plate into which the design has been scratched with specially designed tools which produce a very soft edged line. These were popular in the 18th Century and were frequently produced using brown inks to mimic the crayons and chalks of the period.

Digital Printing
Digital printing is done by computerised printing machines and the ink that is used can be sprayed on like an inkjet, or heat applied in the manner of a laser printer to any flat surface - metal, papers, plastic etc.

Drypoint
This is the simplest method of intaglio printmaking. A line is scratched on the plate with a sharp tool known as a drypoint and the resulting depression and ridges of metal either side of it produce the characteristic effect of drypoint prints.

Editions, Limited Editions and Proofs
Some printing processes (e.g. etchings, engravings, lithographs, linocuts etc) enable the artist to make several copies of a work. Each series of prints made is called an "edition" and usually each print in the edition is marked with a number to indicate how many were produced. Generally if a print is marked as a "Limited Edition" then there should only be one run of it at a fixed quantity and as soon as that number has been made, the plate will be destroyed. This means that the print can never be made again and this action ensures the value of the existing works. Occasionally you may come across a print that has the letters "AP" , “PP” or “HC” instead of an edition number. These are all different types of proofs. AP means that copy is an artist's proof - that is to say a proof printed before the numbered copies of the edition. AP copies are often retained by the artist to give to friends or patrons or to sell outside the published copies. They are usually signed, and sometimes have a number e.g. “I/X” to indicate how many Artist’s Proofs were created. Printers proofs (PP) are generally fewer in number and are usually retained by the printer as examples of the print run and may or may not be signed by the artist . 20 th Century prints often include some marked “HC” which means hors commerce in French – and means “outside the market”.  These “HC” prints are produced in a strictly limited number to act as promotional copies to publicise the availability of an edition for museums and agents. As such they are not intended for commercial sale, however after a period of time it is not unusual for a few to appear on the secondary market where they should be clearly identified as “HC” with a number indicating how many in total were produced. All copies are usually recorded in the list of the artist’s work or ‘catalogue raisonne’ and all copies are normally of high quality. Some collectors prefer to obtain artist’s proof copies as these can be more interesting and are rare in comparison to the numbered copies, and if they are inscribed with a message or dedicated by the artist to a colleague or friend, they can be very collectable.

Engravings are made by warming the metal plate, covering it with printing ink and then wiping the surface over so that the ink only remains in the grooves, lines and indentations. Moistened paper is then applied to the plate and the plate and paper are put through a press (often a device that resembles a clothes mangle) where rollers force the paper onto the plate so it picks up the ink from the lines and grooves. A distinguishing feature of intaglio works is the plate-mark - in other words the indentation of the metal plate's edge on the paper.

Important things to note about prints made by this process are firstly that the ink will usually have a slightly raised texture on the paper as a result of it being taken from the grooves and secondly, that copper engraving plates wear out due to the labour intensive manner of print production (the heating, inking and wiping) resulting in each subsequent print being a little less sharp than the previous. If you are looking at editions of prints made by this method, it is useful therefore to be able to see an early edition of the run in order to assess the deterioration of the plate and any areas of reworking.

Etchings
Etchings are another form of intaglio printing but the lines and grooves in the plate are formed not by a metal tool, but by a chemical process of bathing the plate in acid. A copper plate is coated with a wax that protects the surface from the acid and then the artist uses a tool to draw the lines and grooves of the design in the wax exposing the metal surface. The plate is then immersed in the acid and the areas with the wax coating are protected while the exposed metal is eaten away by the acid, forming grooves. When the plate has been sufficiently "etched" the plate is inked and run through a press as in engraving to produce the print.

Giclee
Giclee prints are generally reproductions of other artworks produced using a form of sophisticated ink-jet printing. Because they are normally managed by a computerised process, the resulting prints are all identical. Unlike intaglio and other types of printmaking in which the artwork is created as a print and executed through a printing process by the artist or printmaker, a giclee is a reproduction of another piece of artwork that could be a painting, drawing, or print. The process is mechanically managed by a computer as opposed to manually handled by a printmaker. The use of computerisation and machinery means that the giclee prints can be produced in large numbers and to an exactly reproducible standard, and can be printed on demand as required.

Hand Colouring
Before the development of lithographic printing, printmakers tended to only produce prints in single colours and then alter them after production using watercolours or inks by hand to colour in the picture. Many 19th century etchings, engravings and mezzotints were hand coloured as this made them more attractive for sale to an eager market, and it is not uncommon to find engravings from newspapers such as the London illustrated News hand-coloured and mounted as artwork. Hand colouring was also used in portrait photography before the development of colour film.

Intaglio Printing
This is a method of printing which includes engraving, etching, and drypoint. The word intaglio comes from the Italian "intagliare" which means "to cut into" and therefore prints made by this method are prints taken from a plate or other flat surface on which gouges, scratches, and other marks have been made so that the ink rests in these impressions.

Linocuts
These belong to the relief print category of work in which the image is created by gouging out lines in the soft lino surface (which is usually attached to a wood block for stability), and then inking the raised remaining areas. Lino cuts can be used to make multicoloured and complex built-up images, as the artist can clean and rework the lino block, removing more surface, reinking and then superimposing the new reduced image on top of the earlier one to form a layered print.

Lithographs
A lithograph is a "planographic" print that is to say a print which is produced from a generally untextured plate that is level. It was developed in the late 18th century, and originally a lithograph was created using limestone slabs, but today metal plates are usually used. Lithography relies on the principle that oil and water do not mix. To produce a lithograph the artist draws the work on a flat plate or surface with a greasy or waxy medium. This image is then fixed with a solution of dilute nitric acid and a substance is rubbed onto the plate to prevent any further grease sticking to the "stone". The plate is then moistened and the water is repelled from the waxy areas. An oil based paint is then rollered onto the plate and the paint only adheres to the waxy areas. A piece of paper is then positioned on the plate and pressure applied using a flat-bed scraper press which rubs the paper over the plate and ensures the pigment is picked up. If the finished work is to be more than one colour, then separate lithographic plates will be drawn by the artist for each colour used and the paper applied to each in turn. Lithography is a very complex printing process and because of this artists will always use the skills of an experienced printmaker or lithographic printing establishment to assist them in their printmaking. Henri Toulouse-Lautrec was a significant exponent of lithography and his influence made it universally popular.

Longevity
The durability of a print or any piece of artwork depends on environmental factors, conservation methods, and the properties of the inks, paints, papers and canvases used by the artist. One of the most significant considerations for papers is the Ph balance. If a paper has a high acid content then it will degrade over time, discolouring and becoming brittle. Inks can also fade with time and light so care should be taken not to place works for long periods in direct sunlight without some UV protection. Good framers will use acid free framing materials where possible to preserve the artwork, and fortunately most contemporary artists producing work for private collectors are aware of the problems of using untested and experimental materials.

Mezzotints
Mezzotints were very popular in the 18th and 19th century and are particularly interesting as they are created using both "intaglio" and "relief" print methods. Mezzotint literally means "half coloured" and it is the delicacy of shading that can be achieved in mezzotints that made them particularly suitable for reproducing popular oil paintings of the period.

Monoprints and Monotypes
These are a mixture of painting and printing techniques that produce single and original pieces of work. A monoprint or monotype is produced from a printing plate upon which the artist has painted the desired image and then applied a single sheet of paper. No two monoprints or monotypes are the same because in between each application of the paper, the paints or inks will have been wiped off the plate and a new painting. These terms are used interchangeably by galleries and artists alike, however strictly speaking, a monoprint may have a recurring motif or element created by the artist using a stencil or a pattern, where a monotype will have no such repeated element.

Plate Mark
This is the slight indentation mark around the edge of a print that is caused by the pressure of the edge of an engraving/etching plate on the paper as they are pressed together.

Relief Printing
This is the opposite of "intaglio" printing and means that the image is produced from an inked raised area being applied to the paper. Most of us have done this form of printing as children using hard vegetables such as a cut potato as the print block. Relief printing methods include woodcuts, linocuts, and collagraphs.

Screenprinting/Silkscreen printing
This is a printing method using a fine mesh "screen". A screenprint is usually worked several times by the artist, once for each colour required. A stencil of each design element is laid on the screen and then paint or ink is poured over the surface and pushed through the openings and the mesh onto the paper. It is particularly appropriate for turning photographs into inked prints as the shading in the photo can be demarcated and then turned into several stencils each being used with a separate paint or ink. It was devised in the 1920s and originally used for commercial purposes. It was made particularly popular in the 1960s by artists such as Andy Warhol who famously used screenprinting to create images of Marilyn Monroe, and Campbell's Soup.

Serigraph
This is another term for screenprinting that was used by artists working in the 1930s in order to distinguish screenprinting as art from the more commercial forms.

Stencil
A stencil has been a popular home decorating tool for many years and it is an essential tool for the screenprinter. It is usually a piece of impermeable card or thin plastic that has shapes cut into it to mask areas and expose others; paint is applied though the holes onto the paper beneath using a brush, sponge or in screenprinting a rubber "squeegee" blade. The stencil is then removed and the image revealed.

Stippling
This is an intaglio process in which the engraver makes dots on the plate in order to create areas of tonal graduation. The density and depth of the dots influences the amount of ink that is held on the plate and therefore the intensity of the resulting image.

Woodcuts
Woodcuts are some of the oldest surviving prints in the world, and as an artform it has been practiced both in the East and West for thousands of years. It is a "relief" printing technique. A wood block is carved into until a raised image is created. Ink is applied and then the block is pressed onto paper to produce an image. Woodcuts often have a distinctive simplicity about them, and as a medium woodcut can produce very stylised images. An artist famous for working with woodcuts is 16th Century Albrecht Durer.