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Friday, April 10, 2009

Noise—Use It

The first in a series of columns about controlling noise

This Article Features Photo Zoom

3 The Add Noise Filter

4 The Texture Filter Offers

Customize Noise
Noise can come in many forms. Organized or random patterns. Small-, medium- or large-sized, or a combination of all three. Hard- or soft-edged. Monochromatic or polychromatic, of any hue and saturation level. Light or dark. Targeted in specific tonal ranges (shadows, midtones and/or highlights). You can customize the look and feel of noise in your images with a relatively simple digital-imaging tool set. Photoshop offers two filters that are particularly useful for noise effects.

5 Imagenomic RealGrain Interface

Noise (Filter > Noise > Add Noise) offers simple controls: Amount controls the intensity of the effect; Uniform and Gaussian control the random pattern generated; and a monochromatic check box. (The color of noise can be controlled more precisely with an adjustment layer. Apply noise in full color to an effect layer—50% gray set to a Blend Mode of Overlay. Make a Hue/Saturation adjustment layer clipped to the noise layer. Use the Saturation slider to control Saturation. Use the Hue slider to control Hue. You even can use the Edit pull-down menu to control a specific color of noise. For instance, to have only red noise, you can change all the blue and green noise to red.)

Grain (Filter > Texture > Grain) offers more control over the patterns generated: Regular, Soft, Sprinkles, Clumped, Contrasty, Enlarged, Stip-pled, Horizontal, Vertical, Speckle. All of them are useful. Horizontal and Vertical create patterns that are so regular that they’re the least likely to be chosen.

If you still haven’t found what you’re looking for, consider third-party plug-in noise generators such as Imagenomic RealGrain or Nik Color Efex and Silver Efex Pro. (My old favorite, Grain Surgery, is hard to find; it can sample the noise structure of any existing element and create a custom algorithm to simulate it on the fly.)

John Paul Caponigro, author of Adobe Photoshop Master Class and the DVD series R/Evolution, is an internationally renowned fine artist and authority on digital printing. Get over 100 free downloads and his free e-news Insights at www.johnpaulcaponigro.com.