Ever print something and have it be slightly different than what you saw in Print Preview? Conversely, ever go into Print Preview and see something that’s just a tad off from what your file actually looks like? For the most part, the differences are probably minor, but why does it happen at all?

This situation usually occurs when the application file contains information that is not under its direct control; for example, OLE (object linking and embedding) objects, or EPS (encapsulated PostScript) files. Here’s what happens in Publisher in these cases, and I’m pretty sure this is standard throughout Office applications:

Basically, when you select Print Preview, Publisher creates a .wmf (Windows metafile) file based on the contents of the publication. This metafile is what you see in the Print Preview window.

OLE objects

The application (that is, Publisher) creates a metafile to display the OLE object on the screen. When you choose Print Preview, it in turn creates a metafile of the Publisher file, including the metafile of the OLE object. So at this point, what’s display in Print Preview is a rendering of a rendering of the actual OLE content.

When you print the file, Publisher calls the OLE server to find out what to print in place of the OLE object, and sends that raw information to the printer for printing.

EPS files

The application (Publisher) uses its built-in EPS filter to create a metafile of the EPS image. Note that Publisher does not use the bitmap preview image that’s usually included in the EPS file. Instead, it relies on its EPS filter, which interprets the PostScript, for more accurate (but still not perfect) rendering.

What gets printed depends on whether you’re using a PostScript-enabled printer or not. For non-PostScript printers, the Publisher passes the metafile it created of the EPS, and that’s what gets printed. For printers that can handle the PostScript language, Publisher passes the raw EPS to the printer, and that’s what ends up on the page.

Keep in mind that the Print Preview also takes into account information about the printer you have selected. For example, if you’ve selected a black-and-white printer, then your preview image is black and white, regardless of whether your publication contains color. Also, the clipping area (margin around the paper edge on which the printer cannot print) varies from printer to printer. This is reflected in the Print Preview image as well. So in general it’s best to select the printer you want before you print preview your publication.