Riso is a Processing library for generating files suitable for Risograph printing. It helps turn your sketches into multi-color prints.
A Risograph is sort of like a photocopier combined with a screen printer. Just like in screen printing, it prints one color at a time, each as a separate layer. To prepare digital files for riso printing, images need to be separated into individual colors, each saved out as a file. The Riso library helps automate color separation and lets you preview of how your prints will look. It makes it possible to turn your Processing sketches into print art!
If you prefer JavaScript, please see p5.Riso.
Set up a base Riso object for each color you want to print with. The constructor takes 4 parameters: the parent applet ("this"), the color, width and height. If you skip width and height, it will default to the canvas width and height.
The color parameter should be the name of the riso ink color you want to print with, like "black", "green", or "red". You can also pass it a Processing color.
This example prepares an image with black and yellow layers.
Riso black;
Riso yellow;
void setup() {
size(600, 600);
black = new Riso(this, 'black');
yellow = new Riso(this, 'yellow');
}You can draw graphic elements on each layer similar to how you would use a PGraphics object. Place the following in setup() to draw an ellipse on the black layer and another on the yellow layer:
background(255); //set the on screen background to be white
black.fill(255); // set fill on the black layer to be fully opaque
black.ellipse(200, height / 2, 300, 300); // draw ellipse on black layer
yellow.fill(255);
yellow.ellipse(400, height / 2, 300, 300);The two ellipses will overlap, which may or may not be desirable when printing. To remove the overlap use the cutout() function:
black.cutout(yellow); // remove pixels from the black layer if they overlap with the yellow layerYou can preview your print on the screen with the preview function:
Riso.preview()Finally, to export the layers for printing, use the print function. They will be saved in the same folder as your sketch as png files, named after the colors you selected.
Riso.print()
Coming soon!