Win16 PostScript Printing Features Disabled Under Windows NT

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1

When running under Windows NT, PostScript-specific printing features in 16-bit Windows-based applications may not be enabled or may not function correctly. Examples of these features include printing EPS (encapsulated PostScript) graphics and performing color separations. In general, these applications will behave the same with a nonPostScript printer driver under Windows NT as they do when they run under Windows 3.1.

MORE INFORMATION

Many 16-bit Windows-based applications designed for graphics production and desktop publishing have printing features that assume the use of a PostScript printer driver. The application typically disables these features if it does not sense a PostScript printer driver. Most applications use the GetTechnology printer escape (API) to determine the type of printer driver. Under Windows 3.1, this escape returns "PostScript" when the current printer driver is a PostScript driver. Under Windows NT, this escape always returns "WinSpool", regardless of the current base driver or minidriver. As a result, the 16-bit Windows-based applications will assume the current printer driver is not a PostScript driver and will disable its PostScript-specific features.

A common end result is that EPS graphics do not print correctly. EPS graphics are composed of PostScript commands that generate a graphic image. Therefore, they cannot be printed except on a PostScript printer. The EPS graphic can optionally include a TIFF (Tag Image File Format) graphic that roughly represents the image the PostScript commands should produce. When an application knows it is printing with a PostScript printer driver, it sends the PostScript commands contained in the EPS graphic as part of the print job. If the application does not sense a PostScript printer driver, it typically sends the TIFF graphic (if there is one) or simply prints a rectangle to show the size and/or position that the EPS file would have occupied on the page. If the application sends a TIFF graphic, the output may appear jagged and blocky compared to the normal EPS output on a PostScript printer.

32-bit Windows NT-based applications do not rely on the GetTechnology escape. Instead, they can call Windows NT-specific APIs to determine the capabilities of the base printer driver, thus PostScript-specific features function normally.