If you are a graphic designer, chances are good nowadays that whatever project you are designing will be printed using a digital printing process. Although there are many similarities between designing for offset printing and designing for digital printing, there are several important differences that are critical to the success of the final printed product.
Digital printing does have some very important advantages over offset printing. The first one that comes to mind is personalization. You can’t really do personalization on an offset press because the image used to create the printed and non-printed areas of the sheet are defined by an indelible image on the metal printing plate.
Also, as run lengths get shorter and shorter, and deadlines get tighter, digital tends to be a better fit.
Here are a few important considerations when designing for digital print.
The chief difference between offset and digital printing is how the image is created on the sheet (paper or other substrate). In offset printing, the printed image is rendered on a metal printing plate that is wrapped around the plate cylinder. Ink is attracted to the imaged part of the printing plate and transferred to a rubber blanket, hence the term “offset”. The image is then pressed into the paper by the rubber blanket. The ink dries by oxidation (air drying), heat, or UV radiation.
In a dry toner digital process, the powdered plastic toner is pushed and pulled onto the substrate (paper) by electrostatic charges from a blanket, roller, or belt. The unfused toner is then “melted” onto the sheet with heat and pressure from the fusing unit. The melted plastic toner tends to sit on the surface of the paper rather than soaking into it like the liquid ink used in offset printing.
There are not many differences in how typography is handled between a digital and an offset printed design. At the end of the day, type and the information that is defined by typographical characters is meant to be read by human eyes (and in some cases like OCR, it needs to be read and understood by a machine). So keep things readable by not reversing type out of light tints or screen builds where no one color is a solid. Also, keep your font point size about 4 at all times. Anything smaller will be very difficult to read. Be sure to embed all fonts whenever possible, and if your program allows for fonts to be saved as outlines (converting the font data into vector data), that can be a life saver if the DFE (Digital Front End) or RIP (Raster Image Processor) does not have your fonts loaded.
Blends and gradients are popular in modern designs, especially for pharmaceutical package design. But they can be challenging for both offset and digitally printed pieces. The most common problem is a lack of transitional smoothness, sometimes called “banding”. There are, however, a few things you can try in your design to help minimize the appearance of banding in your gradient blends. Here are some suggestions:
Some dry toner digital presses are prone to mottling or splotching in lightly screened or tinted areas. This is due to unevenness of the charge values when applied over a large area of the substrate. This is particularly true of many inexpensive uncoated papers, and some very glossy clay coated papers.
Here are a few things you can try:
Be sure to check with your printing services provider for their preferred file formats. Different DFE’s and RIP’s require different file formats and settings within those file formats. If in doubt, always include your source files (InDesign, Photoshop, Illustrator, etc.) even when submitting PDF’s for time and cost savings.
The transparency controls in today’s graphic arts programs are a powerful design tool that can enable a designer to make very cool visual effects in their designs. Unfortunately, used improperly, transparency controls can yield unwanted results in the final printed piece.
Many programs such as Adobe Illustrator or Adobe InDesign have layering and transparency controls. Improperly constructed files may lose their transparency features during the flattening process. Again, the best bet is to double-check with your print provider for best practices and file settings.
A vast majority of digital devices (much like offset presses) can’t print beyond the physical boundary of the printed sheet. If this was a feature of digital presses, they would need to have some way of collecting the “stray” toner to avoid the waste toner contaminating the paper or critical internal componentry. To allow for a printed image that goes up to or beyond the edge of the final trim size, design files must be constructed to incorporate “bleed”. Bleed is the extra amount of printed image that goes beyond the final trim.
Typically, printed pieces that incorporate bleed will require at least 1/8 inch of extra image beyond the trim marks, but in order to be absolutely sure, it would be advisable to check with your print provider for bleed specifications.
If you need to design a project that will contain variable data, you will pretty much have to produce the job on a digital press, as offset presses don’t really provide any variable data or personalization capabilities. The majority of quality control must be provided by the print provider. Most variable data tools allow for a “proofing run” in which a small sample of data can be printed for basic correctness. In some cases, the VI tool will allow PDF’s to be used as “soft proofs”.
As a designer, your task is to produce a design that is “variable data friendly”, by taking into account longer strings of variable information, and making sure there is space for the longer strings, and making sure that the input data from your spreadsheet, CSV file, or database output format is correct in content and in format.
As a designer, it is critically important that you understand how the project will be finished in the bindery process. We already discussed such issues as bleed, and the other potential bindery operations should be taken into account long before your print job is submitted to your printer or print provider. How is the piece supposed to fold? As a designer, you may want to confer with your print provider and provide a “folding dummy” along with your proofs and files. It’s also very important to understand the paper or papers being used. Heavy toner coverage on heavy paper in your piece may cause cracking when folded. Pay attention to paper grain direction, or the need to “pre-score” certain folds before actually folding to reduce cracking.
Ask your print provider if they have finishing equipment that is compatible with digitally printed items. Some finishing gear has hard rollers that could scuff or smudge your pieces as they are folded. Again, the “secret sauce” of a successful digitally printed project is to communicate early and often with your print provider.
For more information on digitally printed pieces, please contact a production printing expert by filling out this form. A production printing and commercial & industrial printing specialist can help answer any questions you might have.