Duotones

page one
In spite of the computer's capacity to differentiate 255 shades of gray, your printer supposedly can only make approximately 50 different tones of the same color. By using duotones on grayscale images, you can add another color which can contribute 50 more shades of differentiation to your printed images and therefore add dimension to your images.
     The procedure I will show you here is a no-frills, basic way to make duotones which can be printed on your desktop printer, or used on your Web site. Duotones intended for use in InDesign, PageMaker, or QuarkExpress documents, or high quality print output require much more complicated processes, and are beyond the scope of this tutorial.
     The images used in this tutorial are larger file sizes than I like to use in these tutorials. However, in order for you to be able to see the duotone effects, which are wonderfully subtle, I wanted to show you a fairly large image, and one of reasonable quality. I've used JPEG's at the Medium compression setting which yielded files that should download in about 10-12 seconds apiece. The Low compression setting would have made 7 second files, but the quality would have made it hard for you to appreciate the effect.
        

To convert using an intermediate Lab conversion, choose Image > Mode > Lab Color. Next, go to the Channels palette, and select the Lightness channel, as shown below.

With that channel selected, choose Image > Mode > Grayscale. An alert box, shown below will appear. Click OK, and your image will be converted to grayscale, using only the luminosity values from your color image.

A third conversion option is to examine all three RGB color channels of your image, and, if one shows good contrast and tones, select that channel, as we did with the Lab channel, and use it to convert to grayscale.
Continue on page two

Copyright © 2000 by Jay Arraich.
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All photographs copyright ©2000 by Jay Arraich
jay@arraich.com