Duotones enjoy a long history as a printing technique that uses two different colored inks (often shades of black and another color, such as blue) to print what is effectively a colored grayscale image. You get a wider range of possible tones out of using two inks than one. Tritones are printed with three inks; quadtones use four inks.
You can mimic this real-world process using the Duotone feature in Photoshop. Its a great way to tone black-and-white photos that have color imbalances or add luster to photos that are too bland.
Regardless of whether you use this as an interim step or save it for last, I suggest creating a copy of your working restoration file (Image, Duplicate), flattening it, and saving it with a new file name to start. The changes made to the file by the Duotone process make continued restoration impossible.
When youre ready, follow these steps:
Convert the photo to grayscale using the Grayscale option, which you can find in the Image, Mode menu.
If you want more control over the conversion process, try creating a Black and White adjustment layer as the top layer in your file, then tweak the settings to achieve the look you prefer. Then convert the photo to grayscale.
If prompted, go ahead and flatten the image. This makes the file use fewer resources.
Again, I prefer starting with a flattened copy of my working file, so I am ahead of the game.
- Confirm that you want to discard color information.
- Select Duotone from the Image, Mode menu.
Select a Preset from the drop-down list (see Figure 7.19) and preview it.
Figure 7.19 The duotone gives the photo a pleasing tone.
The presets are generally named for the colors used. For example, mauve 4655 bl 3 is the third combination of mauve and black. This is a trial-and-error process, so select as many presets as it takes to find something that looks interesting to you.
In Figure 7.19 I am previewing the mauve preset on a photo shot at, you guessed it, the same general location in Canada as the last figure. Rather than a serene landscape, this time my father-in-law captured the fierce action of a plow cutting through the snow.
- Select OK to close the dialog box.
If you like, save your duotone image.
As long as you perform the next step, you dont need to preserve this file.
Drag the duotone into your photo restoration file as a new layer, as shown in Figure 7.20.
Figure 7.20 Drag the duotone into your restoration file.
This may seem odd, but I like converting the 8-bit grayscale duotone back into a 24-bit RGB image for further restoration. This way I am also able to use the duotone to blend creatively with the original photo. It always pays to experiment.
- Continue working.
The one caveat I would mention about duotones is that they are limited to an 8-bit color space. Converting to grayscale doesnt sound all that bad, but what happens is that you convert three 8-bit color channels to a single 8-bit grayscale channel. It doesnt look as bleak at it sounds, but you do lose a smidgen of quality along the way. If you notice the difference (Im not sure that I ever have), consider creating your own type of duotones using color fill layers with Blend Mode set to Color. To blend each color layer:
- Double-click the layer in the Layers panel to open up the Layer Style dialog.
- In the Blending Options section, adjust the Underlying Layer slider to assign the color to a specific tonal region. For example, if you want purples to stick to dark tones, slide the white slider down until the sliders encompass only those tones you want the color to blend with.
- Set the color layers Opacity to blend further.