Sheetfed Offset, Web Offset, Digital : Defining Crossover PointsMay 2011 By Jean-Marie Hershey
In static sheetfed, web offset and digital printing, the term “crossover” denotes the number of impressions at which a per-unit cost advantage can be gained by switching a job from one process to another. Technological advancements continue to enable companies that offer all or most of these processes to be competitive over a wider range of jobs, extending the run length crossover between processes. At the same time, printers that offer most or all of these processes have deliberately coordinated their digital, sheetfed and web printing platforms as closely as possible in terms of capability and quality—revising, even threatening to render irrelevant, the traditional understanding of "crossovers" in the bargain.
Printing Impressions' sources for the following report are Jack Emery, vice president of Data Solutions Management for Sandy Alexander (Clifton, NJ); Bob Anderson, president of Prisma Graphic (Phoenix); and Herb Zebrack, president of Lithographix (Hawthorne, CA).
As usual, the devil is in the details. All press manufacturers have their estimates of where crossover can occur on their equipment; however, when printers have jobs that could be run on either their offset or digital equipment, or on their web or sheetfed offset presses, how they decide where the crossover point is located is frequently more nuanced than a "simple" cost-per-piece calculation. Other considerations include:
Sheet size: A printer can impose more images up on a half-size offset sheet than on almost any sheet for a digital press, meaning that an offset press may prove more productive than a digital machine for a given number of impressions. This gives the advantage to offset over the shorter run.
Turnaround time: Because there is no makeready on a digital press, the technology is well-suited to rush jobs, for which printers can charge a premium. In larger quantities, the premium can justify digital's higher cost per piece vs. offset.
Finishing: A toner-based digital press yields dry, ready-to-process sheets a printer can take to the bindery or finish in-line while his still-wet offset sheets are sitting on a skid. This cedes the advantage to digital over the longer run if this time savings is critical to the job.
Print quality: The fact that a multicolor offset press (CMYK-plus) is built to handle spot colors, whereas many digital production presses can only approximate them from four-color builds, tends to favor offset in smaller quantities where quality requirements are strict.