Creating Artwork
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 be used. 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 will show through. For light colors on dark paper, foil stamping or engraving should be used instead of Letterpress. To build up the color density of a specific color, Letterpress pieces can be run through the press two times using the same color.
- Screens: Grayscale 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, smaller type can fill in. An outline stroke is often applied to allow for ink gain.
- Solids: Letterpress solids will print differently from 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 to allow the type to create a deep impression. When fold-over items are created, the printer will typically back off on 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 be embossed or die cut should be called out in a different color layer (typically magenta). Scores should be 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 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 may occur on the other side of the envelope.
From Wikipedia
Print Series Team
17 March, 2012
