The Risograph is a highly efficient digital duplicator that reflects a similar process to screen printing. First, an original image is burned onto a master copy which is wrapped around the rotating ink drum. Paper is then quickly fed beneath the drum, as ink is pushed through the stenciled master, leaving an imprint on the page. From one master, the Riso can print a high volume of pages quickly and affordably.
The Risograph uses environmentally friendly, semi-translucent, soybean or rice based ink and can only print one color at a time. For duotone or full color prints, colors are layered by switching to the corresponding ink drum and feeding the same paper through the machine. However, Riso ink is never fully absorbed by the paper (it rests atop the page), so allowing adequate drying time is required before adding additional color layers.
We have a Riso EZ 591U and currently have the following spot colors:
Since the Riso prints one color at a time, it does not follow the CMYK model. However, with our four colors, we are able to approximate the full color spectrum by substituting cyan with blue and magenta with fluorescent pink.
The Riso is only able to print on uncoated, toothy, paper. To print, files should be separated into PDFs according to color and set to greyscale. While we can print up to A3 paper, the Riso cannot print full bleed so it is important to leave at least 3/8" margin around the page.
Text and line art should be set in InDesign or Illustrator as vector files to maintain crispness and clarity. All solid shapes should be registration black and set between 5% - 100 % opacity. However, when using large areas of solid color, opacity should be set to a maximum of 90% to avoid jams.
Trapping, or setting minimal overlap between two or more colors, may be used to improve registration and ensure that no white gaps are visible between separate colors.
Fonts should be no less than 5pt. and lines, 1pt.
Please send us your work in an Illustrator, InDesign, or Photoshop folder; or as PDFs or JPEGs between 300dpi-600dpi with no transparency. Also, please include a full color file as reference.
While the Riso is excels in producing specific results, it is not without its limitations. This is part of what makes the Riso beautiful. Please keep in mind that when printing, slight imperfections will occur. These imperfections may include:
paper does not absorb Riso ink and as a result, ink may smudge and/or transfer during heavy ink prints.
when large areas of paper are printed solid colors, ink might not distribute evenly.
when layering colors, the paper feeder may transfer ink. However, this can be minimized by allowing proper drying times and maintaining a clean machine.
when printing more than one color, misalignment between different layers becomes more likely.