High-Contrast Images

Many years ago, some well-meaning soul discovered that super-high-contrast images had an interesting, minimalist look that stripped images down to their bare bones. Andy Warhol, although not best known as a photographer, used this effect in his work, including his famous Marilyn Monroe series. Indeed, high contrast images are easy to achieve simply by using lithographic films intended for reproducing line art.

Litho films have a built in "threshold" that must be exceeded before an image is formed. That is, if a portion of an image is below the brightness threshold of the film, it won't register at all. If the portion of an image is above that threshold level, it is recorded as black. Figure 3.21 shows a black-and-white image at left, with a high-contrast version at right. While this example could have been produced using lithographic film, Photoshop lets you do much the same thing without resorting to special films and litho developers.

Figure 3.21. A normal black-and-white image (left) and a high-contrast version

Figure 3.21. A normal black-and-white image (left) and a high-contrast version

High-contrast images can be created in color or black and white, and can consist of just two or three tones (for example, black and white, or white and a color or two) or may encompass more tones to create a poster-like effect. The important thing to remember when choosing a subject for a high-contrast image is to make sure that the most important part of the subject matter has one of the lightest tones in an image. As the contrast is boosted, the dark tones and most midtone areas will become black, while the very lightest tones will remain white. If your key subject matter is too dark, it will turn black along with the other mid- and deep-tones and not be visible in your finished image.

You can easily create high-contrast images by manipulating Photoshop's brightness and contrast controls. Select Image > Adjustments > Brightness/Contrast, and then manipulate the brightness and contrast sliders to get the effect you want. The contrast control determines the number of different tones in the final image. A typical black-and-white image contains up to 256 different tones; moving the contrast slider to the right reduces that number gradually until, when it reaches 100%, you're left with only black and white. The brightness control adjusts the lightness of all the tones in an image, making the darkest tones brighter and the lightest

Thisdocument is createdwithtrialversion of CHM2PDFPilot2.16.100.Ser|es of six versions of the same image, with the contrast set at 25%, 35%, 50% (top row), and 65%, 75%, 85% (bottom row). If you compare the individual images side by side, you can see how details are gradually lost as the increase in contrast moves them across the threshold boundary, and they change from gray to black or white.

Figure 3.22. Here are six versions of the same image with the contrast set at 25%, 35%, and 50% (top row), and 65%, 75%, 85% (bottom row).

Figure 3.22. Here are six versions of the same image with the contrast set at 25%, 35%, and 50% (top row), and 65%, 75%, 85% (bottom row).

In Figure 3.23 you can see the effect of adjusting the brightness control. The image at top left is the basic head shot at the 50% contrast level. The next three have brightness set for 25%, 50%, and 75%. Learn to use these controls to provide the exact look you want. Often, a 100% black/white image is not the best looking one.

Figure 3.23. Here, the brightness has been adjusted from 25 to 75%.

Figure 3.23. Here, the brightness has been adjusted from 25 to 75%.

High Contrast with Levels

You can use Photoshop's Levels dialog box to give yourself a lot more control over your high-contrast image than the Brightness/Contrast controls alone. This can be especially important when you're working with a color image, as you can adjust the contrast of each of the three primary RGB colors separately.

The Levels dialog box, shown in Figure 3.24, provides a different way of adjusting brightness and contrast. The graph is called a histogram and is used to measure the numbers of pixels at each of 256 brightness levels. Each vertical line in the graph represents the number of pixels in the image for each brightness value, from 0 (black) on the left and 255 (white) on the right. The vertical axis measures that number of pixels at each level. There are three triangles at the bottom of the graph, representing the black point (darkest shadows), midtone point, and white point (the brightest highlights). How these are used will become clearer shortly.

Thisdocumentis crated withtrial version of CHM2PDFPMot2.16.10°. brightness and contrast using a

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