Color separation

From stencil.wiki

For stencil based printing with multiple ink color layers, color separation helps bring the original artwork into the layers (usually greyscale) used to make each stencil. This can be done by hand, analog or digitally.

There are also a number of apps, websites, and other tools that help with color separation, especially for artwork that is already made, such as a photograph or painting.

Methodologies

There are many different approaches to color separation, here are a few distinct ones:

  1. Using riso specific tools, to get quick and easy, full color processing, using the ink colors employed by the riso.
  2. Creating separations while making the artwork by hand layering, either digitally or analogue with transparency/translucency.
    • In this method each layer is dedicated to a single ink (often created in grayscale), rather than creating something full color which is then separated into inks.
    • An analogue version of this can be done using layers of tracing paper or translucent vellum (following some methods of screen printing or other manual color separation).
  3. Using a palette of color mixes which are pre-planned through color charts.
    • Both Natalie Andrewson and Ryan Cecil Smith do different versions of this (see below).
  4. Starting with RGB or CMYK and then channel shifting—to map each channel to a riso color.
    • This can be done manually in a tool like Photoshop or GIMP, or anything else which gives channel access in addition to just layers. The channels are split apart and then colorized to match riso ink colors (and usually previewed with a "multiply" blending mode or something similar.
    • The risoseparator.tools online tool also uses this process.
  5. Using ICC profiles—bits of software that are used in production workflows to map different inks to digital files, built by analyzing printed test swatches (this is the workflow used in a lot of commercial printing and offset that uses custom process colors).
  6. Using a duotone or tritone process on a greyscale image.
  7. Similarly using a posterizing filter to separate an image into spot colors.
  8. Using an analog photography method (screening colors out with filters).

Other resources

Books and zines

Related concepts

There are also other concepts related to color separation that can be useful to understand, such as: