Designing for Letterpress Printing
Ink and Paper
Soft-textured and uncoated solid papers take impressions better than those that are smooth or glossy, and thicker paper allows for deeper impressions than thin paper. Deep impressions will show off the paper appearance, so textured papers such as cotton and linen work well.
Offset printing is done in CMYK mode, which allows cyan, magenta, yellow and black ink colors to mix together to get the perfect hue, viewable from your computer screen. However, in letterpress printing, the inks don’t mix. All ink colors must be selected from the Pantone Matching System, as these indicate the spot ink colors available. Choose from Pantone’s uncoated spot-color selections.
While Pantone ink colors are specific colors, they are typically translucent. The best results will come from using light-colored paper with darker-colored inks, as light-colored inks may not show up on dark paper. Inks print best at 100 percent opacity; if a lighter shade of the color is preferred, a second ink color selection is better than altering the original color’s opacity.
Between one and four Pantone spot colors may be selected for each print job, and each color will be printed from a separate polymer plate. Beware of overlapping colors in the design, as the colors may not turn out as anticipated. Only allow design elements to overlap if absolutely certain the colors should mix. Full designs are better suited for offset or ditial processes.
It is important to note that letterpress printed solids look different from offset printed solids. The paper tends to show through large solids, creating a slightly textured look that’s almost suede-like – some described it a salty. If you large solids and combined with text in the same color, it will require tow separate press runs. Extra runs increase the cost of printing your project.
Software and Resolution
Adobe InDesign, Adobe Illustrator, Quark Xpress and CorelDRAW software programs are all capable of creating the vector files necessary for individual color plates. When sending the final document to the printer, a PDF or .eps (vector) file will be sufficient. Make sure that any other finishing requirements — such as embossing, die-cutting, folding — are also noted and placed on a separate layer for the printer.
In order for the press to provide a clean impression, the document resolution must be high — 800 dpi or higher is recommended — and vector images are preferred. This allows text and graphics to be scaled smaller or larger without sacrificing the integrity of the image. Lower resolutions can cause speckling on the polymer plate, which will look messy when inked and printed onto the finished product.
Letterpress printing has a reputation for printing even small elements very cleanly. However, there is a limit to how small it can go. Type should not be smaller than 6 point or it will not be sharp; in addition, very bold or wide fonts may have ink gain — or bleeding between the letters — when pressed. This can be remedied by adding a white stroke around text characters.
Extremely thin lines will not print well, and it is recommended that lines have a weight of at least .25 points.
With these requirements and tips in mind, go forth and create!