To create a Duotone design, you overlay a grayscale image with two colors, but of course, there’s a lot more design thinking that goes into getting a good result. In this section, we’re going to walk you through some best practices to make sure you do Duotones right.

Prepare the image

Instantly re-toning an untreated image might work for a selfie, but doing so for a professional design will read as lazy. Keep in mind that any photography you work with has likely already gone through some professional adjustments that were intended to enhance the original toning, not your duotones; therefore, you will need to prepare the image before you apply a new, limited color scheme to it. Here’s what you need to do:

A side by side comparison of an illustration and its grayscale form
Start by converting the image to grayscale. Made from an image via Old Book Illustrations
  1. Convert it to grayscale. You can do this easily with the Black & White adjustment filter in Photoshop.
  2. Heighten the contrast. This is most important. Since you’ll only be working with two colors, you need to make them prominent on the final piece. Photoshop has several options for working with contrast, most notably the Levels and Curves adjustment filters. You can also target specific colors in the Black & White adjustment filter and move each slider to increase the color’s saturation (making them darker/lighter in greyscale). The point is to eliminate most of the midtone grays and keep your highlights high and your shadows low.

Choose colors with care

This is where your basic color theory comes in handy. While you can work with an analogous color scheme for a more subdued effect, generally the point of limiting yourself two colors is high contrast, such as a complimentary color scheme. Then, you just plug your selected colors into Photoshop’s Gradient Map adjustment filter or a similar tool.

A side by side comparison of inverted duotones
The same two colors can create drastically different effects depending on how they are implemented. Made from an image via Old Book Illustrations

Be mindful of which colors you choose to map onto the darks and lights of your image. For example, a vibrant, saturated color may be overpowering when mapped onto the shadows. Experiment with reversing the gradient map and different saturation values until you get the result you want.

Don’t limit your duotones to photography

Just because duotones started in the photography sector doesn’t mean they aren’t useful for all your other design projects. An important part of a trend’s renaissance is its reinvention—otherwise, these duotones would simply look dated and vintage. So don’t feel confined to the traditional rules around duotones. They can be a great way to add stylistic flair to illustration, packaging, and whatever else you can come up with.

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