Based on the differences between digital print and offset printing processes, consider how files are prepared before the prepress stage. Subtle differences in how input files are built can make a difference in file size and success of the results. Consider also how best to apply prepress functions such as color management, trapping, and imposition.
Before submitting content files to a digital press, there are decisions to make based on the output that you want and the type of workflow that best meets the required output results and abilities of the digital press.
- Selecting a file format
- Should input files be trapped in Prinergy?
- Should input files be color managed in Prinergy?
- Should PDF pages be imposed in Prinergy?
- Can I proof an offset imposition on a digital printer?
Selecting a file format
Why is vector PDF the preferred format to send to a digital printer?
For most situations, choose a PDF vector output selection as vector files are smaller in size and are compatible with the widest range of digital printers.
If you rasterize a file in Prinergy, you take away the vector and font information that the digital print color server could use to trap and screen, and you lose resolution-independence (scalability). With vector PDF, file sizes are generally smaller and text will always look sharp.
When would it be preferable to send raster data to a digital printer?
When you choose PDF raster, Prinergy RIPs the entire input file into a raster file before sending it to the printer. This takes additional processing time and produces larger files.
Generally, use PDF raster if:
- The input files cannot be printed as vector PDF—for example, DCS-2 files
- The input files use operations that a digital print controller may not support—for example, white or color overprints
- You want to ensure that the final output from the digital printer is an exact match of how Prinergy will render it
Should input files be trapped in Prinergy?
| Decision | Why this method? |
|---|---|
| No | The preferred method for trapping files is to leave the file untrapped in Prinergy and apply traps using the digital front end. Generally, trapping done through the digital front end will provide the best optimized trap for that specific digital press. |
| Yes | If a job was going to be printed as a combination of offset and digital, the job could be initially trapped in Prinergy for offset printing needs, and then the trap removed prior to digital output. At this time, the trap could be reapplied using the digital front end. |
| Best practice guidelines | Based on the specific characteristics of digital presses, and the distinct trapping challenges inherent in these presses (smear trap), it is recommended that trapping be achieved using the digital front end software. |
Should input files be color managed in Prinergy?
| Decision | Why this method? |
|---|---|
| No | Color management covers multiple issues. The following issues are best handled through direct testing with the digital press or by using options available in the digital front end software:
|
| Yes | Using the color management properties in Prinergy can be advantageous when needing to match the colors of two different output devices. In this situation, an ICC destination profile can be identified in an output process template. |
| Best practice guidelines | Other than the need to color match different output devices, color management issues are best handled using the digital front end software. |
Should PDF pages be imposed in Prinergy?
| Decision | Why this method? |
|---|---|
| No | For most imposed jobs, using the imposition software available in the digital front end is the preferred method to use. The software is easy to use and adjust on press, and is well integrated with online finishing add-ons. Additionally, the digital press imposition software is best suited for a streamlined variable data printing workflow. |
| Yes | If online finishing add-ons aren't used, flats are printed and finished in a traditional bindery. Using Preps provides more flexibility to set up difficult impositions and generate complicated flats with marks, creep, and shingling, that meets the needs of traditional bindery equipment. |
| Best practice guidelines | For a majority of jobs, using the built-in imposition software is the easiest and most flexible process to use, especially for variable data printing. |
Can I proof an offset imposition on a digital printer?
By using an imposed output process template, you can scale an offset press sheet to a digital print sheet, to create a mockup of the imposition. Alternatively, you can use the Signature Booklet feature in Workshop to slice the imposition into reader spreads to fit on a digital print sheet. The advantage of Signature Booklet is that the reader spreads will include the marks, creep, and shingling from the offset imposition.