Producing PostScript color separations
Another legacy way of delivering a desktop publication for professional printing is to generate one or more PostScript® files that can be passed along on disk or via modem. PostScript is a page description language developed by Adobe to handle communication between computers and printers. Unlike PDF/X’s single composite file output, producing PostScript output for color separations entails generating a set of black-and-white “seps,” each of the files representing one color component.
When printing your PagePlus publication, you specify a PostScript printer (or printer driver) as the target, and instead of printing out sheets of paper, you check the “Print to File” option. The driver takes care of generating the PostScript file(s), and you deliver the file(s) to the print firm.
In practice, there are so many options for setting up a PostScript driver, and so many different image/platesetting systems in use by commercial print firms, that you’ll need to fine-tune your system settings precisely to match the requirements of the printer with whom you’re working. Good communication with your print partner is really the key here, and cannot be overemphasized. Make sure you’re using a satisfactory PostScript printer driver and have set it up exactly the way the firm has advised.
Among other points to consider are:
-
What type of output you require: a single composite containing all colors, process (CMYK) color separations, or spot color
-
What type of paper your document will be printed on
-
The publication’s page size
-
Whether you want to print each page to a separate file and/or print each separation to a separate file. (Smaller output files are more easily transferable to a service bureau.)
Process or spot color
When offset color separation is being used, it’s important that you understand the two basic ways of separation:
-
Spot-color separation means separation into the individual colors visible on a page (“red,” PANTONE® Reflex Blue and so on). The printed piece typically uses black ink plus one or more spot colors added using various tints of each color.
-
Process-color separation means separation of everything into percentages of the four so-called “process” colors (cyan, magenta, yellow, and black). All printable colors can be expressed, approximately, in terms of process colors.
To set color separation options:
-
Choose Print from the File menu to display the Print dialog.
-
Click More Options and select Separations from the menu options.
-
Check the Enable Separations box, and choose either Process or Spot.
Choosing the color separation type
-
Select Process to select process color output.
This option is only available if the currently selected Windows printer is a PostScript printer.
Normally, process color output gives you four sheets or “separations” per publication page: one each for the Cyan, Magenta, Yellow, and blacK (CMYK) ink components of the objects on the page.
Only the color separations that are selected (checked) in the colors list will be printed. To select or deselect a separation, check or uncheck it.
If the publication uses any PANTONE solid colors, these will appear separately in the color list. Unless you want an another separation for each additional color, click Convert PANTONE® Spot to Process to redefine the PANTONE colors as CMYK.
-
Select Spot to select spot color output.
Spot color output gives you one sheet or “separation” for each color used on each publication page. The colors list shows how many separations will be produced for each page. Only the color separations that are selected in the colors list will be printed.
-
To select or deselect a separation, check or uncheck it.
-
To change a Frequency or Angle value, click to select it, then type the new value.
-
To overprint a specific color, check the corresponding box in the Overprint column (see below).
To output your publication as a PostScript file:
-
Set up a PostScript printer driver as directed by your print partner.
-
Choose Print from the File menu to display the Print dialog.
-
Click the Properties… button to select the PostScript printer, page size and orientation, and other printer settings.
-
Click More Options and select Print to File.
-
From the adjacent pane, check Print to file and enable Print each separation to a separate file.
-
Review prepress settings under the More Options menu options: Bleed, Page Marks, Rasterize, and Picture Control.
-
Click OK.
-
Each time PagePlus restarts, the print options are reset to standard defaults. Double-check your settings in the Print dialog prior to actually printing to the PostScript file. Should you need to make further last-minute changes (for example, a custom setting required by your print bureau, or a limited set of spot color separations), you can do so at this point. Those changed settings will then be “remembered” for the duration of your session. If you wish, you can save the current combination of settings made in the Print dialog as a print profile with a unique name.
Notes:
-
Darkened colors that have not been added to the publication’s palette will be spot-separated incorrectly, using the base (100%) value. To ensure that these colors are properly handled, add them to the palette as described in Managing publication colors and palettes. To use darkened PANTONE colors without adding them to the palette, make sure the Convert PANTONE® Spot colors to Process box is checked.
-
We suggest you set up ICC device profiles for image colors and enable color management so that images in the exported file include correct color space information. You can also specify a device profile for your desktop printer for accurate on-screen proofing of desktop-printed colors. For details, see the topic Managing screen and output colors.
-
The “Registration Color” (shown as
) is available to create custom registration marks for color separations. Should you need to use this color, you’ll find it in the Swatches tab’s Publication Palette.
Selecting other options
Overprint
Select this option so that a specific color component (black is normally selected) prints on top
of the other colors. This may sound strange, but because black ink is very dark, it can be printed on top of other colors without affecting its own color. This reduces “trapping” errors as there is no edge between a black object and the object it overlaps. Because of this, the thin white gaps normally caused by trapping problems will not occur with black objects.
Overprinting is especially useful when printing fine black text on colored tint (shaded) backgrounds, as it is notoriously difficult to prevent trapping problems if the black is not overprinted.
Note that the overprint black setting does not affect how imported vector pictures are color separated.
Convert PANTONE® Spot colors to Process
Select this option if you create your publication using colors from the PANTONE solid color palette (see Color matching with PANTONE® colors) and want to print your page using the standard four-color (CMYK) process separation colors. This will cause the PANTONE colors to be converted to the best process color (Cyan, Magenta, Yellow, and Black) equivalent. The option also allows you to use darkened PANTONE color without adding them to the publication’s palette.
Trapping
Select this option to reduce the alignment problems that occur when printing using several color separations. In brief, if you have two different colored objects which overlap, they will appear on different printing plates. Because printing presses can never exactly align the multiple printing plates, a small gap may be left at the edge where the two objects overlap.
Graphic trapping tries to reduce this error by making the edges where the objects overlap very slightly intersect. The auto-trapping values can be changed, but typically the default values will suffice.
Paper Type
Select the appropriate paper type on to which your printer will print your work. The associated “screen angle” and “screen frequency” settings are automatically set.
If you are a printing expert and require nonstandard settings, select the “Custom” paper type and adjust the values in the printer’s Properties dialog.