How to Make a Duotone
Rich, textured and emotive, two inks make a better halftone

By John McWade
Before & After Magazine

Dateline: December 19, 2003
Volume 1, Number 3


The invention of the halftone in 1883 was a technical and artistic miracle. Ink, which previously had been applied in solid sheets, could now be printed in tiny dots that the eye perceived as shades of gray. The result was an illusion of dimension that made the printed photograph possible and changed the way the world communicates.

But the modern halftone could use some improvement. Shades of gray are no match for the sheer variety in our natural color spectrum. Contrasts of hue, saturation and intensity, for example, do not even exist in black and white. What the halftone could use is greater tonal range.

To achieve this, a duotone is made of two halftones, not just one, and printed in two inks. Two halftones double the printable range of an image. The second halftone is usually a second color, and is usually balanced differently (its shadows may be light, for example, while the original’s are dark). Even better, a duotone has a rich color cast that endows a photo with a sophisticated air unavailable even in four-color printing. Here’s how it’s done:

Two Photos in One!

Photoshop makes a duotone by superimposing two halftones, one of which is (usually) printed in black, the other (usually) in color. The halftones can be identical, but more often they’ll be different (below). It’s important to note that a good duotone can be made only from a good halftone; a second ink can color but will not improve a muddy or washed-out image. You’ll get the best results with the least effort from a photo whose tonal range is evenly distributed from dark to light (right).

Here, two halftones of the same image are slightly different; the top will print black, the bottom blue. The lighter blue will keep the dark areas from becoming overly dense.

A Duotone in Three Steps

A duotone begins as a grayscale image. Open your photo. From Photoshop’s Mode menu select Grayscale, then again from the Mode menu select Duotone. In the Type field of the dialog that appears also select Duotone.

Duotone inks are always spot colors, and the Ink 1 color is normally black (the default). To set your second color, click its color swatch (right), which brings up the Custom Colors dialog. From its Book submenu call up a color library (ours is Pantone*), then to find your color, scroll the palette or simply type its number. Click OK (twice) and watch what happens. To modify your results, select Duotone again from the Mode menu, and repeat.

*Pantone inks are solid colors. Our examples are simulated.

What Makes a Good Second Color?

Think bright to deep Your second ink will add a rich color cast to your halftone. This cast can be warm (reds, oranges and yellows), cool (blues, greens and violets) or neutral (beiges and grays). Its influence can be light or heavy. All can be beautiful—which one to pick is up to your artistic eye.

Keep in mind that on most jobs your second color will also be used to print other elements —type, for example, lines, or a backdrop from which lines are reversed. Your choice, therefore, should be strong enough to stand on its own. For the easiest duotones, use pure, bright colors—reds, violets, greens and such. Deep colors are the most versatile. They stand alone well for type and other elements, and when lightened make beautiful duotones. It’s easier to lighten a color—just tint it—than to darken it, which requires adding black.

One Color Should Dominate

By adjusting the amount of color in the halftones, you can dramatically change the look of a photo. Reducing percentages of color (near right) progressively diminishes the influence of the blue, changing the scene from watery to moody. Similarly, lightening the black (far right) hints at misty morning. To do this, recall the Duotone Options dialog (select Duotone from the Mode menu), click the curves icon next to your color, and in the dialog that pops up (below) enter a value less than 100—try 50%—in the 100 box. This lightens the colored image by half. Click OK and check the results.

(You can also—gulp—bend the curve. You’d do this, say, to keep color out of too-dark shadows.)

Ghosts!

A ghosted image can have a hazy, dreamlike quality, but in black & white it often just looks washed out. A duotone is the perfect solution—its added tonal range will ensure the image remains full and lifelike. To ghost a duotone simply lighten both colors; the darker of the two will dominate.

Duotones Without Black...

This is a step for the brave. Mixing two colors without black can create a breathtaking third, and turn an ordinary photo into a stunner. You’ll have to experiment, though; try complements, opposites, warms-cools and so on. (A strong dark hue and a light neutral nearly always combine.) But how will it print? You’ll need to find a shop that can proof Pantone colors.

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This article is excerpted from Before & After, How to design cool stuff, Issue 27, Vol. 5, No. 3, and is reprinted here by permission. Copyright ©2003, Before & After magazine, all rights reserved. Design more cool stuff! Visit Before & After magazine online at http://www.bamagazine.com/ to buy the current issue, subscribe, or order back issues, including the one containing this article.