No restraints as Adobe's PostScript handles dpi

In the world of professional printing, no one 'prints' any more. Today, everyone 'outputs'.

This is because you may not actually know what it is you are 'outputting' to. The device may be a computer screen (usually 72 dots per inch or dpi), or it could be an image-setter that can handle 4,000 dpi.

John Warnock, founder and chief executive of Adobe Systems, is the creator of PostScript, the language that appears to know no limits when it comes to dpi.

Printing ultimately comes down to a bunch of dots on paper, film or phosphor that make up images and characters. Mr Warnock thought of a way of doing this independent of the 'output device'.

A circle on a screen at 72 dpi may look reasonable but, if it were printed at the same resolution, it would look jagged and awful. If the circle could be described in mathematical terms and the process of creating dots delayed until the resolution of the output device was known, then the results could be varied. That is exactly what happens with PostScript.

Most Macintosh users are well aware of PostScript because it has been at the heart of Macintosh printing since 1985. Windows users are slowly beginning to realise the advantages of PostScript, although not in the same numbers as Mac users. The high end, however, is a totally different story.

Adobe's business development manager for Asia-Pacific in the printing and systems division, Frances White, was recently in Hong Kong talking about the latest version of PostScript, called PostScript 3. It will begin to appear on the desktop some time next year.