Using overlays

You can use medium overlays, page overlays, or both. The choice depends in part on the application. To print the same overlay in different positions on a page, you must use a page overlay. To print the same overlay in the same position on each page of a print data set, you can use either a medium overlay or a page overlay; for this kind of application, however, specifying a medium overlay might be easier. The two kinds of overlays are specified by different procedures. IBM® recommends a prefix of O1 for all overlays.

You can use a form definition to identify one medium overlay or page overlay on a sheet as a preprinted form overlay.

Medium overlays

To include a medium overlay on all sheets of a data set, you can specify the overlay name on the OVERLAYF or OVERLAYB keywords of the OUTPUT JCL statement. Or you can use the form definition to include a medium overlay on some or all sheets of a print data set. You do not need to modify the print data set to print a medium overlay on every sheet.

If you want to print a medium overlay without merging it with data from the print data set, use a utility such as IBM Page Printer Formatting Aid (PPFA) to specify the constant-forms function in the form definition. For example, in PPFA, use the CONSTANT subcommand. When the constant-forms function is specified, PSF prints the medium overlay on a page by itself. Thus you can, for example, print an overlay on the back side of each page in a print data set with no variable data on that side.

When you use a medium overlay, you can specify different overlays for different copies of a page. For example, you can print one copy of a page with an overlay, the second copy of the page with a different overlay, and the third copy with no overlay.

The number of medium overlays that you can use on a page depends on the complexity of the overlays, the amount of storage required for fonts and page segments in the overlays, and the amount of storage required for the page. You can specify a maximum of nine medium overlays in a subgroup–eight medium overlays and one preprinted form overlay.

Page overlays

You can include a page overlay in line data or XML data by creating a page definition that calls in the overlay to print, relative to a print line (in traditional line data), a layout (in record format line data), or an xlayout (in XML data). For line data, you also can code an Include Page Overlay (IPO) structured field in the application to include the overlay on a particular page and to identify the print position of the overlay on that page. You must list the overlay name in the page definition used for printing the line data before you can call it by using an IPO structured field. You can use a utility such as PPFA to create a page definition that includes a page overlay or lists the overlay for inclusion by an IPO structured field. See AFP structured fields included in line data for more information about using structured fields.

To include a page overlay in a MO:DCA-P document, use the facilities provided by a document layout program, or specify the IPO structured field in the document. To use an IPO structured field, you must also list the overlay in a Map Page Overlay (MPO) structured field on the same page.

The number of page overlays that you can use on a single page depends on the complexity of the overlays, the amount of storage required for fonts and page segments in the overlay, and the amount of storage required for the page.

Preprinted form overlays

Preprinted form overlays can be better than regular medium or page overlays for simulating preprinted forms or colored paper because the overlay data is included after all other data has been applied, and then the data is merged. To identify a preprinted form overlay, create a form definition that identifies the overlay as a preprinted form overlay. A medium overlay is identified as a preprinted form overlay with a medium preprinted form overlay local ID keyword (X'D2') on the MMC structured field; a page overlay is identified as a preprinted form overlay with a Resource Object Include triplet (X'6C') on the PMC structured field that is specified with a PFO object type.

Keep in mind:

Only one type of preprinted form overlay is allowed on each page on a sheet. For example, a page preprinted form overlay is ignored if a medium preprinted form overlay is identified. Also, if more than one of the same type of preprinted form overlay is identified, only one is used and the others are ignored.

For more information about preprinted form overlays, see Mixed Object Document Content Architecture Reference, AFPC-0004.