Few would deny the classic beauty of a grayscale (black and white) photo. Many ordinary pictures can be rendered more elegant simply by removing their colors, but none more so than portraits. Amidst the kaleidoscope of colors on social media sites, forums, and blogs, a grayscale avatar can stand out as unique and memorable. Even more distinctive is an image in which a single color is used in place of black, or perhaps even a second color is used to replace white.
An image consisting of one color is called a monotone. White isn't a color, but rather the absence of color--just like paper showing through a printed image indicates the absence of ink. Thus, in a grayscale or black and white photo, black is the only color, and that makes it a monotone. Adding a second color--either by replacing white or in addition to the first color--creates a duotone; third and fourth colors create tritone or quadtone images respectively.
Here's how to use Photoshop CS4 to create monotones and duotones for your avatar portrait. The following instructions are completely non-destructive and preserve your original image. This technique is intended for users who are comfortable working with layers and creating or editing gradients.
1. With your color avatar image open in Photoshop CS4, check the Layers and Adjustments panels in the Windows menu to display the tools you need.
2. On the Adjustments panel click the Vibrance icon (the one with the inverted triangle) to add a Vibrance adjustment layer to the image.
3. As soon as you click the icon, the Adjustments panel will change to display two sliders, Vibrance and Saturation. Drag the Saturation slider all the way to the left to convert your image into grayscale. You now have a grayscale avatar; if this is all you want, stop here and use the Save for Web & Devices command from the File menu to create a JPEG, PNG, or GIF. Continue to the next step only if you'd like to use a color other than black.
4. At the bottom of the Adjustments panel click the arrow button at the left to back out of the Vibrance settings and return to the main Adjustments panel view. Once there, click the Gradient Map icon (bottom row, second from the right) to insert a Gradient Map adjustment layer above the Vibrance adjustment layer.
5. Once in the Gradient Map dialog, click the arrow beside the displayed gradient and select a two-color gradient from the pop-up gradient palette. Use something other than a black-to-something gradient to see how the black and gray tones of the image are replaced by the color on the left of the gradient. For instance, if you choose a blue-to-white gradient, your image will become blue ink on a white background. If you don't find a suitable gradient on the default gradient palette, click on the gradient itself to open the Gradient Editor. There, you can define your own gradient colors.
6. If you have only Photoshop's default gradients downloaded, you'll need to install more from the program's built-in set. Click the Presets arrow to view another eight sets of gradients. The best one I found for faces is a two-color combo set called "Simple." Choose it and click Append to load it. Note that if you check the Reverse checkbox, you can reverse the color concentration.
7. For a simple monotone effect, use a gradient that transitions from a color on the left to white on the right. To replace white in your image with another color--to create a blue on orange duotone image, for example--change the color stop on the right from white to that other color.
[Pariah S. Burke is the author of Mastering InDesign CS3 for Print Design and Production (Sybex, 2007), and other books; a freelance graphic designer; and the publisher of the Web sites GurusUnleashed.com, WorkflowFreelance.com, and CreativesAre.com. Pariah lives in Portland, Ore.]
This story, "Photoshop Gradients for Monotone or Duotone Effects" was originally published by Macworld.