What is Digital printing?
Digital printing refers to methods of printing from a digital based image directly to a variety of media.[1] It usually refers to professional printing where small run jobs from desktop publishing and other digital sources are printed using large format and/or high volume laser or inkjet printers. Digital printing has a higher cost per page than more traditional offset printing methods but this price is usually offset by the cost saving in avoiding all the technical steps in between needed to make printing plates. It also allows for on demand printing, short turn around, and even a modification of the image (variable data) with each impression.[2] The savings in labor and ever increasing capability of digital presses means digital printing is reaching a point where it will match or supersede offset printing technologies ability to produce larger print runs at a low price.
What is Offset printing?
Offset printing is a commonly used printing technique where the inked image is transferred (or “offset”) from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a water-based film (called “fountain solution”), keeping the non-printing areas ink-free.
Which process should I use for my print project?
Use this checklist to help decide:
Quantity. Offset printing has a front-end cost load. Short runs may have a high unit cost. But as quantities increase, the unit cost goes down with offset printing. Very short runs can be much more cost effective with digital printing; while larger quantities are likely to have a lower unit cost with offset printing.
Printing medium. Do you need or want a special paper, finish or unusual printing surface, or unique size? The options are increasing continually for digital, but offset printing still offers the most flexibility.
Color. Digital presses use four-color process printing. If you need only black ink or one or two ink colors, offset printing may offer a more cost-effective solution. If you need four-color printing, digital may offer advantages in lower up-front costs.
More on color. If you’re planning to print using the Pantone® Matching System, offset printing will give you the best match, since it uses actual Pantone® ink. Digital printing only simulates the color using a four-color matching process, so some digital printers may offer less accurate color matching on projects.
Turnaround. If you need it fast, digital usually offers quicker delivery.
Proofing. Digital offers accurate proofs since you see an actual sample of the printed piece. Accurate color proofing for offset printing can be expensive.
Customization. Without question, digital printing offers the most affordable way to customize marketing materials, direct mail pieces, letters, etc.
What is Gang-run printing?
Gang-run printing describes a printing method in which multiple printing projects are placed on a common paper sheet in an effort to reduce printing costs and paper waste. Gang runs are generally used with sheet-fed printing presses and CMYK process color jobs, which require four separate plates that are loaded into the press. It takes up to 250 sheets for a “make ready,” which is the process of getting the plates inked up and the ink levels set correctly.
Printers use the term “gang run” or “gang” to describe the practice of placing many print projects on the same sheet or piggybacking a project on a vacant, unused portion of a print sheet. Sheet-fed presses are generally “full sheet” (28” x 40”), “half sheet” (28” x 19”), or “quarter sheet” (13” x 19”). In offset printing, the first sheet costs more than the next 1,000. Gang-run printing allows multiple jobs to share the setup cost. For example, a 28” x 40” sheet can hold 9 4” x 6” at 5,000 or 18 2,500 postcards (each card takes 4.25” x 6.25” on the sheet to accommodate full bleed. Gang-run printing has been one of the driving forces in the large drop in the price for full-color printing.
Advantages
- Extremely economical--many print jobs share the same print run, which reduces manpower, plates, prep time, and press wash-up labor.
- Reduces waste--less paper goes unused.
Disadvantages
- Lack of paper stock choice--you must choose the paper stock common to all the projects on the same sheet
- Lack of color control--color balance on a gang print run is difficult to maintain. Since so many other print projects are placed side by side, a gang print project is harder to control for color quality issues
- Ghosting--because an adjacent project may have a heavy solid color that may affect your final result
- Hard to accommodate custom print quantities--normally
- Reprints cost more--rerunning a print job from the sample plate would mean reproducing unwanted copies of adjacent projects sharing the same sheet or plate
- Harder to get custom colors or cut--by nature of the press run, it is harder to get custom spot colors, varnish effects, or coatings.
- Timing issues--gang printing customers normally need to be more patient with their client, since it takes more time and effort to coordinate all the jobs through the singer viewer.
