Tag: Design

Designing for the Risograph & What to Expect When Submitting a Request

The more you use the Riso the easier it will become to design with Riso in mind. Here are some design tips to diminish Riso printing variations:

  • Lower ink opacities to <80%-95%.
  • Set overlapping colors and color blocks and background colors to <80% opacity.
  • Limit the number of colors you use. (Four colors at 100% = 400% saturation.)
  • Leave the top 2” of your image blank, or lightly inked. 
  • Use font size 6pt or higher.

Surplus Prints

You may have extra copies of some pages in your order. For Riso prints, the IC starts a print run with a 10-20% excess. This is because a certain number of prints jam, or misregister beyond a ¼”, and we throw these out. 

However, we will include any extra copies that go through undamaged. This is why you may have a different number of copies than you ordered. For example, if you order 10 copies of a 3-page book, you may have 12 copies of pages 1-2 and 10 copies of page 3. 

You will not always have extra prints, so make sure you order the correct amount without accounting for extra copies.

There is No “Perfect” in Riso

There are some common imperfections in a Risograph print. These imperfections are part of the Riso printing process

Registration Marks

You may see crosshair or crop marks in the four corners of your prints. The IC adds these to help the printer align the color separations in your print. If you have a “full bleed” print, there will probably not be registration marks. You can add in the notes to leave them out. However, the registration is more likely to be askew without them.

Ink smudges

Riso ink dries through absorption. Similar to a newspaper, Riso prints never fully cure. Rubbing the ink with your finger, even once” dry”, can result in smudging. Ink can also transfer from one sheet to the next during the printing process.

Roller Marks

Roller marks typically show up as a rhythmic line down the center of the paper towards the top. They are more common in 2nd, 3rd, and 4th color passes on the Riso, but they can happen on a 1st pass.

Misregistration

Each color is printed separately, so colors rarely match up perfectly. We aim to keep our registration within  3/16” between colors, and 1/4“ for double siding.

Cleaning up a Finished Print

Riso ink marks can sometimes be removed with light erasing. Prints that will be heavily handled (e.g. book covers, or flipbooks) can be sprayed with fixatives to help prevent smudging.

For more information on Riso printing, check out our complete Riso Guide.

Risograph & Imaging Center Technician: Teddy in Winter 2021

Color Systems & Color Spaces

Understanding RGB vs. CMYK vs. CMY

The primary colors of light RGB (Red, Green, and Blue), represent a visual range that, in theory, can produce any color that can be seen by the human eye. Mixing with light is an additive process. (When you add all the colors together, they make white.)

Printing is a subtractive color process and uses the opposite colors, CMY (Cyan, Magenta, and Yellow) to mix and produce an image. Working with physical colors (i.e. dyes, pigments, inks) brings with it the limitations of your materials. In theory, cyan, magenta and yellow, all together should produce black. But in reality, the pigment usually turns to a muddy, inconsistent brownish-black. (The shade of brownish-black is dependent on your materials.)

This is why Black (or K for Key) is added in addition to the CMY gray-blend, giving you a sharper, richer, darker black.

So, when you are printing in CMYK, about half of your grays and blacks are made with an even blend of CMY, and the other half is a layer of black printed on top. In theory, all of your CMY channels should have the same information as your black channels, just at a lighter value.

Overall, subtractive color spaces tend to have a wider spectrum of colors to offer. This is why most people work in an RGB color space such as Adobe RGB 1998 or ProPhoto RGB, instead of CMYK. Side note: All screens use additive color.

What is a Color System?

A color system is a set of colors that represent a specific visual spectrum.* These few colors are mixed together to create a limited usable range, and that range is called a color system. Examples of a color system include RGB, CMYK, and Lab.

* “Appendix A.” Understanding Digital Photography, by Joseph A. Ippolito, Thomson/Delmar Learning, 2003, p. 372.

What is a Channel?

Photoshop organizes your chosen set of colors (e.g. RGB or CMYK) into channels, dividing up your image information by color. For RGB and CMYK, Photoshop also includes a composite channel. Each channel is in grayscale and uses a mask to store each color’s information. You can edit this mask to alter the look of your image and how the channels are mixed.

In RGB and CMYK, you can use the Channel Mixer to change the amount of color information on each channel.

What is a Spot Color?

An additional color that is not a part of an established color system or mode.

For More Information

Linkedin Learning: Understanding CMYK vs. RGB
Linkedin Learning: Understanding Spot Colors
Linkedin Learning: Spot Colors