Simple duotones
This view of Prague (left)
has been rendered in
tonesreminiscent of a
bygone era. After turning
the image to grayscale,
twoinks were used for
theduotone, neither of
themblack. This gave a
light, low-contrast
imagecharacteristic of
anold postcard.
Duotone Options screen shot
The curve for the blue ink (above) was lifted in
the highlights in order to put a light bluish tone
into the bright parts of the image and also to help
increase the density of the shadow areas.
Much of the art of traditional black and white
printing lay in making the most of the limited tonal
range inherent in the printing paper. A common
tactic was to imply a wider tonal range than really
existed by making the print contrasty. This suggested
that shadows were really deep while highlights were
truly bright. The success of this depended on the
subtleties of tonal gradation between these extremes.
A further technique was to tone the print, adding
color to the neutral gray image areas.
Modern digital printers have opened up the
possibilities for toning well beyond that possible in
the darkroom. The range of hues is virtually
unlimited as you can simulate all those that can be
created with the four-color (or more) process.
Creating a duotone
Starting with an image, even a color one, first
turn the file into a grayscale (see pp. 224–9) using,
in Photoshop, the Image > Mode menu. This
permanently deletes color information, so you
need to work on a copy file. Similar results can be
obtained in the Sepia Tone effect, a menu option in
almost all image-manipulation applications.
Now that you have a grayscale image you can
enter the Duotone mode, where you have a choice
of going it alone or loading one of the preset
duotones. If you are not familiar with the process,
use the Duotone Presets (usually found in the
“Presets” folder of Photoshop). Double-click on any
one to see the result.
Retaining subject detail
In the original image (above left), there was so much
atmosphere it was a pity to lose the color. But the
resulting duotone, with a green second ink, offers
its own charms (above right). To reduce overall
contrast and allow the green ink (chosen via the
Color Picker dialog box, bottom left) to come
through, it was necessary to reduce the black ink
considerably—as shown by the Duotone Curve
dialog box (center left). The low position of the
end of the curve in the dialog box (center left)
indicates a low density of black, but the kinks in
the curve were introduced to increase shadow
contrast and retain subject detail. The lifted end
of the curve shows that there are no real whites:
the lightest part still retains 13.8 percent of ink,
as shown in the top box labeled “0:” in the
Duotone Curve dialog box.
Clicking on the colored square in the dialog
box (see opposite) changes the color of the
second “ink.” Bright red could give an effect of gold
toning; dark brown, a sepia tone. This is a powerful
feature—in an instant you can vary the toning
effects on any image without any of the mess and
expense of mixing chemicals associated with the
darkroom equivalent.
If you click on the lower of the graph symbols,
a curve appears that tells you how the second ink
is being used, and by manipulating the curve
you can change its effect. You could, for example,
choose to place a lot of second ink in the highlights,
in which case all the upper tones will be tinted.
Or you may decide to create a wavy curve, in
which case the result will be an image that looks
somewhat posterized.
In Photoshop, you are able to choose to see
Previews. This updates the image without changing
the file, thereby allowing you to see and evaluate
the effects in advance.
You need to bear in mind that a duotone is likely
to be saved in the native file format (the software’s
own format). This means that to print it you may
first have to convert it into a standard RGB or CMYK
TIFF file, so that the combination of black and
colored inks you specified for the duotone can be
simulated by the colored inks of the printer. This is
the case whether you output on an ink-jet printer or
on a four-color press.

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