Letterpress We use metal plates to hold sharp detail as the impression is debossed on the sheet.
Letterpress printing is a technique of relief printing using a printing press, a process by which many copies are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. A worker composes and locks movable type into the “bed” or “chase” of a press, inks it, and presses paper against it to transfer the ink from the type which creates an impression on the paper.
In practice, letterpress also includes other forms of relief printing with printing presses, such as wood engravings, photo-etched zinc “cuts” (plates), and linoleum blocks, which can be used alongside metal type, or wood type, in a single operation, as well as stereotypes and electrotypes of type and blocks. With certain letterpress units it is also possible to join movable type with slugs cast using hot metal typesetting. In theory, anything that is “type high” or .918 inches can be printed using letterpress 
Letterpress printing was the normal form of printing text from its invention by Johannes Gutenberg in the mid-15th century until the 19th century and remained in wide use for books and other uses until the second half of the 20th century. Letterpress printing remained the primary way to print and distribute information until the twentieth century, when offset printing was developed, which largely supplanted its role in printing books and newspapers. All forms of data collection were affected by the invention of letterpress printing, as were many careers such as teachers, preachers, physicians and surgeons and artist-engineers. More recently, letterpress printing has seen a revival in an artisanal form.
Letterpress can produce work of high quality at high speed, but it requires much time to adjust the press for varying thicknesses of type, engravings, and plates. The process requires a high degree of craftsmanship, but in the right hands, letterpress excels at fine typography. It is used by many small presses that produce fine, handmade, limited-edition books, artists’ books, and high-end ephemera such as greeting cards and broadsides. Because of the time needed to make letterpress plates and to prepare the press, setting type by hand has become less common with the invention of the photopolymer plate, a photosensitive plastic sheet that can be mounted on metal to bring it up to type high.
To bring out the best attributes of letterpress, printers must understand the capabilities and advantages of what can be a very unforgiving medium. For instance, since most letterpress equipment prints only one color at a time, printing multiple colors can be challenging. When offset printing arrived in the 1950s, it cost less, and made the color process easier. The inking system on letterpress equipment is less precise than on offset presses, posing problems for some graphics. Detailed, white (or “knocked out”) areas, such as small, serif type, or very fine halftone surrounded by fields of color can fill in with ink and lose definition. However, a skilled printer overcomes most of these problems. However, a letterpress provides the option of a wider range of paper, including handmade, organic, and tree-free. Letterpress printing provides a wide range of production choices. The classic feel and finish of
letterpress papers takes printing back to an era of quality and craftsmanship. Even the smell of the ink, more apparent on a letterpress-printed page than with offset, may appeal to collectors.
While less common in contemporary letterpress printing, it is possible to print halftoned photographs, via photopolymer plates. However, letterpress printing’s strengths are crisp lines, patterns, and typography.
Creating files for letterpress is similar to conventional printing with these exceptions:
Ink Color: Files are created using spot colors, not CMYK or RGB. A spot color is specified for each color to use. Typically one or two colors are used.
Paper Color: Dark ink on a light paper gives the best image. Inks are translucent and the paper color shows through. For light colors on dark paper, printers use foil stamping or engraving instead of letterpress. To build up color density, letterpress pieces can be run through the press two times using the same color.
Screens: Gray-scale images can be used if made with a coarse screen (85 line or less). A second color should be used instead of screening a color in most cases.
Thickness: Art must be above ¼ point and with no hairlines.
Fonts: Type must be five points or larger for best results. For reversed type the point size should be 12 point or larger, as smaller type with its thin stroke can fill in, or plug. An outline stroke is often applied to allow for ink gain.
Solids: Letterpress solids print differently than conventionally printed lithographic solids. While letterpress does lay down a thick film of ink, the process tends to show the texture of the sheet. Also, solid areas do not give the appearance of depth that fine type and thin lines do. Solid areas can also cause the paper to ripple, especially on thinner sheets.
Registration: Letterpress does register well, however, it does not have the capabilities of modern offset printing. Trapping and key lines do not work well in letterpress printing. A blank area should be incorporated between colors. Black and very dark colors may be overprinted over lighter colors.
Depth: The type depth is dependent on the paper. Typically, letterpress papers are thick and soft so the type creates a deep impression. When making fold-over items, the printer typically backs off the pressure to avoid embossing the backside of the piece.
Image and File Prep: Letterpress excels at line copy and type, so vector images work well. Crop marks should be shown as a register color. Images need to bleed (extend past the trim line).
Die cut, Emboss and Scores: These effects work well with most Letterpress paper. Images to emboss or die cut are called out in a different color layer (typically magenta). Scores are typically indicated with a cyan line. Any intricate shapes or patterns should be reviewed with the printer. For thick cover stocks many printers use a “kiss cut” (partially through the stock) rather than a score.
Envelopes: It is best to print on the flap of a ready-made envelope. Other areas of the ready-made envelopes can be printed, but bruising can occur on the other side of the envelope.