Printmaking in the Modern Era

I have studied several methods in Fine Printmaking, and will go over the basics of them here, and provide some links for readers interested in learning more.

For all the types of printmaking, there are common characteristics.  Each type of printmaking method uses a matrix, which is the surface containing the image to which the ink is applied and used to transfer to the paper.  The matrix can be made of any of a number of materials, including zinc or copper for intaglio prints, linoleum or wood blocks for block prints, slabs of stone or treated aluminum for lithography, and screens for screen prints.  Ink is applied to the matrix in different ways, depending on the technique being used.  When the inked matrix is applied to paper (you can print on other surfaces as well, but for the sake of our discussion, we'll say paper), usually using a press, it creates an impression of the image.  As the printmaker creates impressions, he or she may decide to change some aspect of the print. This can include changing the matrix itself,
the colors of ink used, the type of paper, or the conditions of the ink, the paper or the press.  Any impressions created during this experimental phase are called Trial Proofs, and if they are signed or used at all, they will be designated as such by the signature line, marking them with the initials C.T.P. (Color Trial Proof) or simply T.P. (Trial Proof). Once the printmaker has determined the conditions that he or she would like to use for several identical impressions, he or she will create an edition, a set of individual impressions that are identical to one another.  Once the printmaker prints the full edition (how many is up to the individual), they will be signed and numbered by the artist, specifying the order in the edition, and the total number in the edition (e.g. 1/100, 2/100, 3/100).

Why are there so many different methods of printmaking?  When you have the opportunity to look at each of the different types of prints, you will see noticeable differences in the types of images that can be created from each one. Some methods exhibit highly detailed lines, while other prints are composed more of broad regions of solid colors.  The print method is chosen for what type of image the artist is trying to express. Not to steal my own thunder, but Wikipedia has an excellent explanation of each of these techniques. I will, nonetheless, summarize the different methods here.

Intaglio (in-TAL-yo) is from an Italian word meaning "to cut into," and that is essentially what you are doing when you make the plate. The plate is usually something very hard, nowadays zinc or copper, in the olden days, they used to use wood also, though it didn't hold up as well. The image is cut into the plate somehow, and the method for doing so defines the subcategory of intaglio, and these include etching, aquatint, mezzotint, engraving, and drypoint.
For all intaglio printmaking, your plate will have lines carved into it, representing the image, and blank space in between, which will be blank. However you have made your image, the printing process is the same. The ink used is a thick, pasty ink, and is, at first smeared all over the plate, and gently pressed into its surface to get it into the grooves of the image. Next, various stiff pieces of cloth and paper scraps are used to remove the excess ink from the top surface (between the etched lines), until the only ink remaining on the plate is what is captured by the incised lines. Next the plate is laid on a press bed, a soaked, blotted piece of printmaking paper is laid over it, followed by felt blankets that protect the press bed and even out the pressure. When the paper and plate are rolled through the press, the paper is literally pushed into the grooves in the plate, where it picks up the ink and keeps it. When you pull the paper off of the plate, Voila! There is your image on paper!
Each of the different methods mentioned above simply determine how the image got onto the plate.
For etching, a metal plate is coated with a smooth waxy layer called a ground, and the image is gently scratched or pulled out with a needle or other materials to leave the exposed metal plate. The plate is then submerged in an acid or redox bath, which gently removes the top layer of the exposed metal a bit at a time, until it has achieved enough depth to hold ink. The plate is removed from the bath, washed off, and the ground removed with a solvent. The lines produced by this method are very durable and sharp, and will produce the most number of reproducible images.
A variation on etching is called aquatint. In this technique, the plate still has a ground to define where the etching will take place, but this ground is made up of a layer of very fine particles of rosin dust that is allowed to settle over the plate evenly, but not completely covering it, and so that tiny little spaces between the particles leaves the plate exposed. This layer is then gently melted onto the plate. These particles allow the artist to create varying shades of gray, depending on the depth of the etching of the little spaces between the rosin particles. Next, the traditional waxy ground is used to cover up any portions remaining white in the resulting image. The plate is then submerged in the acid bath for a carefully measured amount of time (predetermined by trial and error), then removed, and the lightest tonal areas are covered up with ground. The plate is resubmerged in the acid, and the process repeats itself until the plate has as many tones, from light to dark, as desired for the image. Aquatint is one of the more challenging techniques, but if done correctly, can produce soft even tones of gray, though it is difficult to produce true, even, black tones.
To get true, rich, even black tones and delicate gradations, the method to use is mezzotint. In this technique, the entire blank plate is engraved with tiny pits using a hand-held tool called a mezzotint rocker. (See image)
This tool contains hundreds of tiny sharp teeth on its curved edge, and the tool is rocked back and forth over the surface of the plate, thousands of times. This technique is incredibly labor intensive, but, in the end, you wind up with a plate that should print a smooth, velvety black. Once the plate is completely pitted, the artist takes various scraping and smoothing tools, either scraping off a portion of the burr to produce gray tones, or scraping and smoothing it back down to white.
Another technique for creating tiny soft lines is engraving. Using an engraving burin (a sharp, V-shaped tool) the metal plate is literally carved into to create the lines. The burin will actually remove the metal from the plate as it goes along. These lines print softer (usually) than etched lines, and they tend to wear out more quickly.
One final technique to mention is drypoint. Similar to engraving, the lines are incised by hand, but in this case, the tool is a hard needle, and the line is simply pressed very hard into the metal plate--very little, if any, metal is removed. The resulting lines can be very soft and fuzzy, and these lines will wear out much more quickly than the other techniques.
Each of the intaglio techniques serve a specific purpose, in order to create the type of image the artist wants.

Block printing is also generally known as relief printing, which is the opposite of intaglio, in that, on this type of plate, the carved away part will be the blank background, and the top surface of the plate will produce the printed image. One excellent example of block printing is stamping, as is popular today with scrapbookers and craftspeople. In this technique, the matrix is composed of wood, or a block of linoleum, and often that determines the name of the technique: woodblock printing or linocut printing.
For both techniques, the image is usually sketched out on the surface of the plate, then various carving tools are used to remove the top surface of the plate where the background will be. Once the image is left behind in relief, it is ready to be printed. Instead of pressing the ink into the surface with great force, as in intaglio, the ink is gently rolled onto the surface. The image is usually transferred to dry paper, and can be performed by running it through a press under very light pressure, or can be transferred to the paper by gently rubbing on the back of the paper with something smooth, like a wooden spoon.
Block printing techniques have the advantage of being able to achieve bold areas of black and white, but not a lot of gradation, as can be seen by the example image.

I'm sorry to have to lump these two together, because they really have nothing in common, except that they are two techniques that I have little to no experience at. The one thing that the two techniques do have in common is that you can use both of them to create very large editions of prints (in the thousands, if done correctly).
So here goes.

Screen Printing or Serigraphy uses a fabric screen to create a stencil, through which the ink is applied to the paper. The image can be applied to the screen through a variety of methods, from simple cut-out designs to photographic methods, using screens that have a UV sensitive emulsion on them. One popular screen printing kit is made by Riso Company in Japan, and is called Print Gocco. This method uses a photosensitive screen for creating the printing stencil.

Lithography uses the fundamental property of oil-water repulsion to create the printing surface. The plate is created traditionally on a smooth limestone block, but modern lithography also uses specially treated aluminum plates. The image is drawn onto the surface with a waxy (oil-like) lithography pencil. Once the image is drawn on the way the artist wants, the plate is chemically treated to adhere the image to the plate, without changing the oily nature of the image surface. There are special photosensitive plates created for lithography as well, enabling artists to transfer virtually any type of image to the plate. To print the plate, the surface is wetted with a thin layer of water, then the oil-based ink is rolled over the plate with a large, rollingpin-like brayer. Because the oil-based ink "likes" the oil-based pencil of the image, and "dislikes" the water on the part of the plate with no image, the ink sticks rather specifically to the image on the plate. The paper is carefully laid over the plate, and a special press applies even pressure, transferring the ink to the paper.

So say you are a magnificent painter, or you do amazing works in colored pencil, oil pastels, or, well, Crayola Crayons, but have no desire to learn any of the aforementioned techniques for creating archival reproductions of your work. All you really want is to be able to sell perfect reproductions of some awesome original. Enter the digital print.
Many artists sell prints from original images that have been digitally scanned and then printed, either on their own printers or on someone else's (such as a gallery).
One type of digital print that you will see quite often is called a giclee (zhee-CLAY) print. This was a term coined in the early '90s to mean any print made on a specific type of high resolution inkjet printer using special archival inks on archival paper. The original giclee prints were made using a printer made by Iris Graphics. Nowadays, I believe there are several companies that make printers able to achieve the same results, and thus qualify as giclee printers, including HP and Epson.
Some artists purchase their own printers that are able to use archival inks and papers, and are able to offer their own prints without an outside gallery or print shop. In my own research, I have found that HP's new Vivera inks are reported to last for 100 years, and archival papers made with a variety of textures can be found at art suppliers or paper goods suppliers. It is unclear at this point what distinguishes a giclee print from these other digital prints, but it appears that the overall quality and durability of the image is similarly excellent for both.
As is obvious from the description, the process for digital prints is completely different from any of the other traditional printmaking techniques. Anyone reading this who has toiled over getting colors to come out right and eliminating dust from your digital image can tell you, the digital print is not without effort. Once the image is satisfactorily digitized, however, it is easy to see that the artist can now produce a limitless edition of prints, thus illustrating one reason why the digital print has less value than a traditional print--lack of rarity. To solve this problem, many artists create an artificial edition size, and are then on their honor to create no more after that. Some artists will even go so far as to destroy the digital image once the edition is completed.
Many artists strongly object to the idea of selling digital prints, since they were not technically created by the artist's own hands. In my own humble opinion, I think that digital prints are an economical way for the artist to share his or her original work and still retain all the reproduction rights. Many artists are able to sell their digital prints for less than $25 each, and each of the collectors can have a part of a limited edition for a reasonable budget.
So the up-side to digital prints is that they are usually perfect reproductions of the artist's work, and are reasonably inexpensive to collect. The down-side is that they are not created by hand and they may not be in a limited edition.