Design made simple; with clip art, anybody can become an artist - includes buyer's guide of clip art software packages and related articles on illustration, paint and image-editing software and clip art for logos and newsletters

Home Office Computing, Oct, 1993 by Steve Morgenstern

DEFINING THE DIFFERENCES

When choosing clip art, you should consider whether you'll be better off with bitmapped images, vector images (also called object-oriented graphics or line art), or with black-and-white or color graphics.

Bitmapped clip art images are dot-by-dot representations of a picture. Since each dot in the image is determined individually, bitmapped graphics can be highly detailed (scanned photographs are saved in bitmapped formats). Editing a bitmapped image can be easy: In a paint or image-editing program, you use pencil, paintbrush, and eraser tools. It also can be tedious, since each individual dot must be changed in the process. Bitmapped clip art is your best bet when shading and detail take precedence.

Vector graphics are composed of descriptions of shapes, such as lines or curves, that together make up a picture. So selecting an element in a drawing (that is, one of the objects that make up the graphic as a whole) and altering it is easy because that object can be isolated from the others that form the piece. You may also perform more technical editing, such as altering the curve of a line. Because of vector graphics' point-to-point orientation, primary tools in these programs (such as illustration software) are simple shapes like arcs and ellipses.

With vector graphics, you can change the size and shape of an image and still print it with smooth-edged lines at the full resolution of your printing device. Take a crisp-looking bitmapped image and enlarge or reduce it significantly (as you would if you were to use the same graphic for your letterhead logo and a banner promoting your business), and the edges will develop jaggies.

An alphabet soup of graphic formats fall into the bitmap and vector categories but a few formats are the most widely supported. On the bitmapped side, the TIFF format straddles both the PC and Mac worlds, while PCX and BMP are exclusive to the PC arena and MacPaint is limited to Mac 72-dots-per-inch, black-and-white images. In the vector world, EPS (Encapsulated PostScript) is supported on both the PC and Mac and is the standard for object-oriented artwork created for PostScript printers. CGM (Computer Graphics Metafile) is the most widely supported vector format in PC presentation programs. Finally, PICT is supported by every Mac program that accepts graphic images. Both bitmapped and vector artwork can be saved in PICT files.

The demand for color art for presentation purposes has created an upsurge in the availability of color clip art. Your first instinct may be to select color over black-and-white artwork. Think twice about the way you'll be using the artwork before making this decision, though. Color art files are larger and more complicated to edit and may produce unpredictable results when output to a black-and-white printer. Clip art vendors who are particularly sensitive to this problem--Masterclips and Multi-Ad Services, for instance--create their color art using shades carefully chosen for attractive results when output in black and white, or else they bundle colorto-black-and-white conversion utilities, as Presentation Task Force does.