PUB2000: Page Shrinks Slightly When Printed to Some Imagesetters (198250)

SYMPTOMS

When you print a publication to an imagesetter at certain resolutions, the pages print smaller than they are supposed to. For example, if you print to a Scitex Dolev at 2540 dpi, everything prints approximately 1.2 percent smaller than it should. A letter-sized page prints about 10.87" tall instead of 11".

If you print the same publication at a different resolution (2400 dpi, for example), the pages print the correct size.

NOTE: This problem is not confined to Publisher; it happens in all other programs that use the Windows PostScript printer driver to generate PostScript. This problem only occurs if you are running Windows 95 or Windows 98; it doesn't occur on Windows NT.

CAUSE

By default, the unit of measurement used in the PostScript page description language is the point. One point is approximately 1/72". When the Windows PostScript printer driver creates a print file, it has to convert measurements from the actual printer resolution (in dpi) into points.

The PostScript printer driver for Windows 95 and Windows 98 only allows three decimal place precision for the conversion factor. This means that it uses a conversion of factor of 0.028 to convert inches to points at 2540 dpi. This is not very accurate; the correct conversion factor should be more like 0.028346.

The Adobe PostScript driver for Windows 95 and 98 (available from Adobe Systems, Incorporated) is slightly more accurate. It allows for four decimal place precision. To convert inches to points it uses a conversion factor of 0.0283. However, this is still not precise enough.

The PostScript printer driver used by Windows NT 4.0 and later allows for five decimal place precision. While not perfect, this is accurate enough to make the errors unnoticeable.

WORKAROUND

Method 1: Print at a slightly different resolution.

If the PostScript Printer Definition (PPD) file for your imagesetter only supports "problem" resolutions (1270 dpi, 2540 dpi, and so forth), print using a different PPD file that supports similar resolutions which do not cause the problem (1200 dpi, 2400 dpi, and so forth.) Publisher ships with a PPD (PostScript Printer Definition) file called the Microsoft Publisher Imagesetter (MSGenbw.ppd). This PPD supports most popular imagesetters, and uses a resolution of 600 dpi. If you don't have this driver listed, you can add it by doing the following:

On the Start menu, point to Settings and then click Printers.
Double-click the Add Printer Wizard.
Follow the instructions on screen. When the Wizard prompts you for the manufacturer and model of the printer, click Have Disk.
Click Browse.
Browse to the C:\Program Files\Microsoft Office\Office folder. Click OK.
Click OK again.
On the Printers list click MS Publisher Imagesetter. Click Next.
Follow the instructions to complete the Wizard.

Method 2: Manually increase the scale of the print job

You can use the Windows PostScript printer driver to increase the scale at which your pages print. For example, if you must print at 2540 dpi you can do the following:

On the File menu, click Print.
On the Printers list click the imagesetter you will be printing to and then click Properties.
Click the Graphics tab.
Increase the number in the Scaling control to 101%.
Click OK.
Make any other printer settings changes you want and then click OK.

NOTE: This method only increases the scale of your pages by 1% (instead of the actual 1.22%.) However, this may be close enough for your purposes.

MORE INFORMATION

You can predict if you will encounter this problem by dividing the number 72 by the resolution of your printer. If the answer requires more than three decimal places to display, the page will print in an incorrect size.

Printer Resolution   Actual Conversion   Conversion Factor  Percent Error
------------------   -----------------   -----------------  -------------
   300 dpi              0.24                0.24              0
   600 dpi              0.12                0.12              0
  1200 dpi              0.06                0.06              0
  1270 dpi              0.05669291          0.057            -0.54
  2400 dpi              0.03                0.03              0
  2540 dpi              0.02834646          0.028             1.22