Creating a Duotone Image in Photoshop

Yesterday, Richard Hales began an introduction to Black and White images. In conjunction with that, I wanted to present an oldie-but-goodie technique that you can use to spice up your black and white images – you can create a Duotone image. Duotones were originally created to allow the use of two inks (usually black and one other color) to be printed on an offset press as halftones (images made up of tiny dots, like you’d see in a newspaper or magazine). Having two colors instead of one adds a subtle richness to the image.

Let’s see how we can do this in Photoshop.

If we want to create a duotone image, we have to first start with a black and white image. More, specifically, we need a grayscale image, because only a grayscale image can be converted into duotone with Photoshop. So, use your favorite technique to create your black and white image, and then (using a copy, of course!) flatten the image. Here’s a quick example, starting with this color image:

 

Using a channel mixer adjustment layer, I create this black and white rendition (you can use any technique you like):

Now, we have to prepare the image for Duotone. First, flatten the image (Layer > Flatten Image).

Next, convert to grayscale (Image > Mode > Grayscale).

Since the image is already black and white, we can safely ignore the warning about discarding the color information. Click Discard and continue on.

Now we can see that our image is in grayscale (see the caption bar information at the top of the document window?):

If your document isn’t grayscale, you won’t be able to perform the next step (the menu item will be grayed out). Choose Image > Mode > Duotone… and you will see this dialog box:

The first thing you’ll want to do is change the Type from Monotone to Duotone. This will add a second ink swatch to the mix:

At this point, even though we have Preview enabled, there is no change to the image. After all, it started as a black and white, and we have only black and white defined. Let’s click on the white swatch – this brings up the Color Libraries:

No, pulling down the Book dropdown list will give you a whole bunch of different color libraries, but for now we’ll stick with the default Pantone solid coated. Click the color rainbow near the bottom, and scroll to find Pantone 7526C, and select it.

Your image changes immediately. Click OK to get back to the duotone dialog box:

Already, this image has a lot more depth and richness than the plain black and white!

Now, you may be wondering, “what is that box with the diagonal line?” Well, that is actually a curve that you can use to adjust the specific colors in your duotone. For example, if we click on the curve next to the new Pantone swatch, we get this:

Adjusting the curve will change the amount of the brown Pantone ink that is applied depending on the tonal range of the image. The height of the curve is the amount of ink, and the gradient at the bottom shows the tonal range where the ink is applied. The default is a smooth ramp with more brown in the shadows. We can change it to modify the effect: Just click and drag on the curve to add points:

There are a whole lot of presets available in the dialog box, and you can spend hours trying them out and examining the curves to see how they work. Here are a few examples:

If you feel really adventurous, you may find that some of the presets are Tritone (3 inks) or Quadtone (4 inks). The possibilities are truly unlimited:

I hope you’ll try this one out – a quiet little corner of Photoshop that is capable of energizing your black and white images! (provided that you remembered to convert to grayscale!).