Printing on printers that support multiple resolutions

When you are printing on a printer that can print at more than one resolution (pel density), you might see fidelity imperfections in your printed output. Fidelity problems arise when your data was formatted with resources (for example, fonts) at one resolution, but the printer used resources at a different resolution to print the job. Some fidelity problems that can occur are:

• Data no longer exactly fits in a box on a form.
• Columns for tabular data overlap or are spaced wider than intended.
• Right-aligned data might show a ragged right margin.
• Minor typeface differences might occur.

To avoid fidelity problems in such cases, your system programmer can define separate resource libraries for each resolution that the printer supports. For example, your system programmer can define 240-pel font, overlay, and page-segment libraries and 300-pel font, overlay, and page-segment libraries. When PSF is printing on printers that support multiple resolutions (that is, printers printing in automatic mode), PSF can select resources from the appropriate resource library.

To select the correct resource library, PSF must know the resolution of the resources that you used when you formatted your data. The format resolution can be specified in several ways:

• Your system programmer can use the PSF installation exit APSUX07 to specify a format resolution.
• For fonts mapped in MO:DCA-P data, the application can specify the Font Resolution and Metric Technology triplet (X'84') on the MCF2 structured field directly in the print data set or resource to indicate the resolution. See Mixed Object Document Content Architecture Reference, AFPC-0004 for more information about this triplet. Two applications that generate this triplet are DCF and OGL. See the documentation for your application for more information.

  PSF uses the resolution in the MCF2 structured field to select the font library only; PSF does not use this resolution to select the overlay or page segment library.

• You can specify the RESFMT keyword on the OUTPUT statement (see RESFMT).

  PSF uses the resolution format specified in the RESFMT parameter to select the overlay and page segment libraries. PSF used the RESFMT parameter to select the font library only if the MCF2 structured field does not specify a font resolution.

• You can let PSF use the default system library.

If the printer is in automatic mode and, therefore, is capable of accepting resources at multiple resolutions, PSF looks for the first specification of the format resolution in these areas and order:

1. The PSF installation Exit 7 for Resource Management begin-data-set call
2. The Printer Inventory or the PSF installation Exit 7 for Resource Management initialization call
3. The data stream in the Map Coded Font format 2 (MCF2) structured fields in the Font Resolution and Metric Technology triplet (X'84')
4. The JCL OUTPUT statement RESFMT keyword

If the printer is not in automatic mode and, therefore, is accepting resources at a single resolution only, PSF uses the resolution reported by the printer to select the resource libraries.

PSF uses the determined format resolution only when selecting a system library to search for resources. If inline resources exist or if you specify a user library, PSF searches them first.

Whether you specify the format resolution to PSF or not, you can control what action PSF takes if PSF finds a mismatch between the resolution of the fonts used to format the data and the resolution of the fonts used to print the data. A font–resolution mismatch might occur if, for example, the printer is not printing in automatic mode or the system programmer did not set up separate resource libraries for each resolution. In the event of a font–resolution mismatch, the default action is that PSF continues processing the data set.

//AFPUSERB JOB ...
//STEP1 EXEC PGM=USERA
//OUT1  OUTPUT CHARS=GT10,RESFMT=P240,OVERLAYF=O1FOVLY,FORMDEF=STOP,PAGEDEF=A06462
//PRINT DD SYSOUT=A,OUTPUT=(*,OUT1)

For a complete description of how to handle printing on printers that support multiple resolutions, including a description of the system programmer tasks involved, see PSF for z/OS: Customization.