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ATPM 3.07
July 1997

The exciting news about Amelio’s departure from Apple and the upcoming release of System 8 completely overshadowed important news in the graphics field. QuarkXPress 4.0, Painter 5.0 and MetaCreation’s SOAP (the first product of the merger between Fractal Design and Metatools) are a few of the exciting products recently launched into the market. With such a huge suite of graphic programs, and with more being release almost daily, it is difficult to decide which program(s) to use for your graphics projects. One solution is to work on a single project with two or more applications, interchanging the file back and forth between applications until you reach your desired goal.

With this in mind, I decided to discuss file formats this month.

The terms “vector” and “bitmap” graphics are mentioned here, so for those of you who would like more information on these terms, please refer to the article describing them in ATPM 3.04.

The most common file formats are listed below and some of their properties are compared in the accompanying table:

Macintosh PICT: Picture Files: This is the most common file format used on Macs for pixel images. Note that during JPEG compression, image quality will be lost, especially with higher compression settings. Also, the PICT format is not supported in non-Mac environments, but can be converted using specialized utility software.

Advantages: Widely supported on the Mac market, which means that files can be easily interchanged between most Macintosh programs. However, this format is not so good for high end jobs.

Macintosh EPS: Encapsulated PostScript: This is the most comprehensive file format used on Macs for most types of images (vector and pixel-based).

Advantages: The only way to go for Desktop Color Separation (film making) and clipping paths (dropping out of images).

Universal TIFF: Tagged Information File Format: This format was invented by Aldus (the company who wrote Freehand and was bought by Adobe). It is less common than PostScript but still has a big market for pixel images. Illustrator has recently added support for it. LZW compression uses a lossless quality compression scheme.

Advantages: It fairs much better than PostScript for low-end printers that do not support PostScript, giving much clearer images on printouts.

Universal GIF: Graphic Interchange Format: The power of this format derives from its limitations. Images have reasonable file sizes and a crispness enjoyed by few other formats. Its built in (lossless) compression format is particularly suitable for blocks of solid color. It also supports progressive decompression (where the image is re drawn in phases), which is useful for web graphics.

Advantages: Very common for web purposes. Of particular note is the GIF format’s ability to handle transparencies.

Universal JPEG: Joint Photographers Expert Group: This group identified elements that, when removed, have the least effect on an image’s quality. The result is smaller file size. JPEG format is now commonly used with many high end printers to reduce printing time.

Note: Be careful not to over-compress images. Lost detail cannot be regained and is particularly noticeable in images containing text.

Advantages: Smallest file size in most cases and support for progressive decompression (when the image is re drawn in phases on the web) make it the format of choice for web images.

A final consideration is what type of color formats are supported. RGB is what your monitor uses; CMYK is what printers use; and indexed color is used to keep file sizes small.

Since formats are updated every now and then, it is possible that newer versions will support features that are not supported as yet. Next month I can discuss how to exchange the formats between applications and platforms or go on to work on some 3D animation stuff, it all depends on the amount of e-mail I get rolling!

Copyright © 1997 Jamal Ghandour, jghandour@atpm.com. Jamal Ghandour is a “Senior Graphic Designer” and “Computer Section Manager” at CSS & GREY(Kuwait). He also works as “Creative Art Director” at Swiftel international communications.

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