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RISOGRAPH HANDBOOK v 1.0 DESIGNING FOR THE RISO PAGES 4-11 Designing for the Riso Designing an image for printing on the Riso is quite a bit different than designing for inkjet or laser printing. The key difference is that the Riso is only loaded with one or two spot color drums at a time meaning your range of colors on each print will be limited. You will also need to account for how your color layers will be halftoned and layered in the final print to achieve your desired outcome. After you have a proof in hand any changes you would like to make to the design will require new masters to be burned. Learning to work within these limitations will be the most important aspect to creating a successful print. Design basics The most basic way to prepare a design for Riso printing is to create a separate grayscale image for each color layer you intend to print. This can be done either in Photoshop, Illustrator, or by hand to be scanned into the MF 9450 directly. These grayscale images can then be burned as a master on any color drum of your choice. 4 Below are all of the considerations you need to account for while preparing your design. Each of these can have a significant impact on the successful outcome of your prints. Read them carefully and consider how they may apply to your design. A. Riso inks The Riso prints with eco friendly rice-oil based inks that don’t conform exactly with CMYK, Pantone, or any other color standard outside of their own. Here are a few important factors about Riso inks to keep in mind while designing your image: There aren’t many color We have 10 spot colors available that can be printed 2 colors at a time. This means you will need to work within a very limited color palette. You can expand that palette by layering inks, running your print through the Riso multiple times, or even using colored papers Furthermore you will have a hard time comparing the colors you see on your computer screen with the printed Riso inks. You will want to reference the color chart regularly as you work. They’re all transparent This is important to remember when you are layering your inks or planning to print on a colored paper. You’re going to see some of whatever is underneath each ink layer, with lighter inks typically allowing more to pass through. This can be incredibly helpful for layering inks to create new colors. 5 They print one at a time While the MF 9450 can be loaded with 2 colors at once, each color will print completely one before the other. This means that all of color A will print before any of color B with color B laying on top of A. You won’t be able to print color A on top of B in the same printing operation. They’re a bit thick and sticky Laying down too much ink on the paper can cause the paper to stick to the ink drums resulting in splotchy, ugly prints. It is typically a good idea to avoid having large areas of solid color in your designs or to reduce the density of your ink in those areas. The amount of reduction will vary between colors and how much area you’re trying to cover, but 80% is usually a good target number. Check the color chart to see how this reduction will impact your selected colors. Your paper can only take so much As Riso inks are layered on your paper the paper with start to get saturated. As the paper reaches its saturation point it will begin to reject ink and take on a splotchy appearance. Try to keep your combined ink density in any given area below a total of about 200% or so. This is even more critical in prints that will combine more than 2 colors with additional passes through the Riso. Every paper will have a different saturation point so your results may vary. 6 They take a few prints to get going It can take a few prints for the ink to flow into a fresh master and fully print your image at saturation. Expect to print 10 or so throwaway prints to allow the master to charge. They never really dry That’s right, Riso inks never fully dry. Even prints that have sat for weeks can still have their ink smudged. Allow your prints to set for at least an hour before heavy handling. Prints with larger ink densities may need more time. Prints that are going to be ran through the Riso a second time for 3+ color printing will need to set for much longer. Speak to a DWC Assistant about printing with more than 2 colors. B. Printable area The maximum paper size printable in the Riso is Tabloid/Ledger 11 x 17 with a minimum ¼” margin on all sides. Leave a margin of about ¼” on all edges of your design. The paper feed rollers run along a 2” path down the center of the paper. Avoid heavy ink buildup in this area if you plan on printing more than 2 colors. The rollers will pickup excess ink from the paper surface and leave a track mark on your prints. Light track marks are common and can usually be erased with a simple rubber eraser. You’ll want to avoid heavy ink usage in this area if you are planning on making a double-sided print. Heavy ink in this area from the first pass can create extra smudges when the paper is flipped over. 7 C. Halftoning In the process of creating a new master you will need to decide how you want your image burned to the master screen, either through a variety of halftoning options or as a dither pattern. Screen-covered These are your classic halftones. You have three frequency options to choose from. The higher frequencies result in smaller halftone dots while the lower frequencies will have a more identifiable halftone pattern. Grain-touch Grain-touch creates a randomised diffusion dither pattern of your image. This will be the most neutral halftone option as it provides the most accurate translation of your design to the master. 8 D. Overprint & knockout When designing your image you will need to decide how your color layers interact when they overlap each other. Overprint Overprinting will print both overlapping colors in full so that one color lays on top of the other. You cannot overprint the same color on top of itself as all of a color is printed in a single pass. Overprinting is needed to mix colors together in your design. Knockout A knockout will remove the bottom color when colors overlap in your design so that they no longer overlap. This can be particularly helpful when you don’t want to see a dark ink through a lighter color. 9 D. Registration It is important to remember that Riso printing is a physical process and the two print drums may not always print in perfect alignment with each other. This can lead to unintended gaps in your print. Trapping Trapping is a process where you add a little bit of overlap for each adjacent color layer so that your layers will slightly overlap each other. This overlap will allow for some misalignment in the printing process without exposing gaps in your image. Print position The MF 9450 allows each print drum to be repositioned both vertically and horizontally using the touch panel to correct for some misalignment. While this can be very helpful in correcting registration issues it is not able to correct for any rotational registration problems. 10 Paper feed tray Paper needs to be evenly placed in the feed tray with the guides secured tight to your paper stack. Loose paper will misfeed and cause registration issues or worse. Printing with 3+ colors You will run into registration issues any time you intend to print with more than a single pass through the Riso. You may need to add registration marks to your image and work with a DWC Assistant to print your design correctly. 11.
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