Start with a simple, graphic image, and open it in Photoshop. Convert the image to Grayscale in the Image>Mode menu, and if it isn’t already, immediately convert to 8 Bit color depth (also in Image>Mode). Pause here to create a snapshot of this history state by clicking on the camera icon found at the bottom of the History palette. This will make it easy to return to this stage of the process, which you may want to do in later stages.
Next, convert the image to Duotone mode, again found under the Image>Mode menu. This will bring up a window allowing you to choose between Monotone, Duotone or additional color combinations. I prefer Monotone, as this creates a strong, graphic Risograph effect, yet still allows for a variety of possibilities going forward. Click on the color swatch next to the Ink 1 layer to choose the color you’d like to use. The brighter the better, as far as I’m concerned, and this goes with the idea of a Risograph too. When you’re happy with the color you’ve chosen, click OK. You’re now looking at what’s effectively a stand-in for the single color screen that would be used in Risograph printing.
Here you have reached a creative fork in the road. You can add a contrasting color by creating a color fill on a layer above your image (you’ll first need to switch to RGB mode in the Mode menu) and then changing the layer mode to Difference as I’ve done in the two-tone camera example here.
Don’t be afraid to experiment with other layer modes such as Screen and Lighten, though, as different combinations have their own unique appeal. When you’re happy, click on the top layer and type Command-Shift-Option-E (or CTRL-Shift-Alt-E on Windows) to combine all of the layers below into a merged single layer above, which is easier to work on going forward.
Note here that you still have the single Monotone layer as the background image. This presents an opportunity to experiment both with the modified Duotone we’ve now created or with the more traditional Risograph look of the original monotone layer.
If you want to add a more authentic Risograph feel, consider adding a halftone screen to that monotone image. This is done way back in the early stages of the process, after converting to Grayscale but before converting to Duotone. To go back to this stage of the process and experiment with halftone dots, click on the Snapshot you saved earlier, found at the top of the History palette.
To add a halftone to the once-again Grayscale image, click on Pixelate>Color Halftone found under Photoshop’s Filter menu. The resulting dialogue box allows you to enter the maximum size of the halftone dots and will require some trial and error until you find exactly what you like. Too small and the effect is lost on the naked eye. Too large and it becomes clumsy and too abstract. There’s no “right” way to do it, so whatever you find visually appealing is appropriate. (Had you waited to apply this halftone when the image contained color information, as the filter name suggests the halftone screen would consist of multi-colored dots. Because we want single-color dots, the halftone has to be applied to a grayscale image.) When you’re ready to proceed with the remainder of the color effects, convert the image to RGB before continuing.
An alternative approach to a monotone Risograph effect would be to open an image and convert it to Grayscale and then use a color fill layer to apply a single color over the entirety of the image. This produces a slightly different look, as it adds color to the lightest areas of the image and allows a level of control Duotone Mode doesn’t.
To do this, desaturate the image or convert it to Grayscale and then back to RGB. Then, click New Fill Layer from the Layer menu and choose Solid Color. This brings up the New Layer dialogue, which allows you to click on a color from the dropdown menu (which you’ll be able to modify with the picker once you click OK) as well as setting the Mode to Screen. This replaces all the grays in the image with monotone colors, more accurately the way an actual offset print or Risograph screen would. Click OK to open a color picker window and then OK again once you’re satisfied with the color.
Another opportunity for experimentation presents itself here by way of the Layer Mode for the color fill layer. Screen mode is fairly traditionally Risograph in nature, while Color Dodge mode allows the darkest pixels in the original grayscale image to come through—adding a bit of contrast and punch to the otherwise literally “monotone” image.
Whatever method you use to get here, the last step for a true Risograph -inspired image is to add a bit of imperfection by way of artificial noise. To do this, click Filter>Noise>Add Noise, then experiment with different percentages for the amount, as well as switching between Uniform and Gaussian distribution—again deferring to whatever appeals to you in this rule-free creative environment.
Lastly, if you’d care to play with contrasting colors a little more, save the monotone Risograph you just created (like the grainy blue example included here) and then go back and repeat the process with a different color such as red or yellow. Then, combine the images by copying one to a new layer over the other and changing the layer mode to Overlay. This makes for an interesting combination of the two tones in a sort of vintage feel that works well with the spirit of the Risograph without overpowering the original tones. Dialing down the opacity of the overlay also helps ensure the effect remains subtle.
In the end, there aren’t a lot of rules when it comes to creating this Risograph-inspired look, and it’s a great way to add interest and some funky style to an otherwise straightforward image.