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2 4 G R A P H I C S P R O J U L Y 2 0 2 2 G R A P H I C S - P R O. C O M 2 4 G R A P H I C S P R O J U L Y 2 0 2 2 G R A P H I C S - P R O. C O M AMAZING IMAGE EFFECTS WITH FILTERS LEARN THE BASICS OF PHOTOSHOP FILTERING S I G N A G E & P R I N T I N G T H E D I G I T A L E Y E | S T E P H E N R O M A N I E L L O W hen an image really makes your eyes pop, chances are good that filters were involved. Like many other techniques, filters have their origin in the analog world of photography. Photographers use filters to correct or enhance lighting and to create or adjust anom- alies of perspective. Digital filters take on these tasks and expand them far beyond the colored circular frames of glass that filter light as it enters the lens. Digital filters adjust focus, eliminate unwanted arti- facts, alter or create complex selection masks, breathe life into less-than-perfect scans, and apply a dazzling range of effects previously unavailable to the traditional photogra- pher. Filters also have the capability to destroy anything recognizable in an image and turn it into a swirling mass of pixels gone wild. FILTER BASICS Filters are simply mathematical formulas that alter the numerical values of pixels in specified ways. Certain char- acteristics of an individual pixel can be modified including its hue, saturation and brightness and its position in rela- tion to other pixels. When these effects are applied to a group of pixels, great variations can be achieved over a specified range, following specific constraints. Some fil- ters work subtly; others can be brash and flamboyant. Some effects gain strength when used gently and reap- plied; sometimes a filter can be mitigated or softened by fading. e application of filters can be non-linear so that modifications can be made at any time. FILTER TYPES If you look in Photoshop's Filter menu, you'll see 17 different categories. Within each of these submenus are numerous filter effects. (Fig. 1) Rather than go through the list filter by filter, let's divide them up by what they can do. CONSTRUCTIVE FILTERS Constructive filters are those that are used to mod- ify and enhance images for printing or screen display. is list includes filters that blur, sharpen, alter color, reduce noise, or otherwise enhance pixel conf igurations. Four groups of filters provide tools to help improve Fig. 1: If you look in Photoshop's Filter menu, you'll see 17 different categories, each with an array of filter options. (All images courtesy Stephen Romaniello) Fig. 2: The effect of the Gaussian Blur filter used to soften the focus of a selected background.