Implementing Quality Control
Digital printing is one of the leading sectors in the printing industry. Both the large format printing and desktop publishing fall into the commercial printing category. These two industries demand a quality criteria for various printing applications. Implementing commercial printing quality control must be prioritized in all printing jobs.
There are various forms of printed media that are available today. They are used in desktop, and large-format printing. The following enumeration includes plain and specialty paper, cardboard, photo paper, vinyl (commonly known as tarpaulin), garments, shirts; and all applicable rigid media such as glass, wood, and ceramics.
In printing terminology, the negative output is called the printing anomaly. This refers to the resulting print output with below minimum acceptable quality, and bearing printing discrepancies.
These printing anomalies can be spotted more easily on rigid media, unlike their flexible media counterparts. Anomalies often include: incomplete printing, incorrect color due to improper color profile, incorrect color/hue/tint, incorrect ink saturation, and color banding (vertical and/or horizontal).
The common causes of these printing anomalies include the type and quality of ink being used, hardware accuracy, the type of media being printed, and the software that processes the image to be printed. The RIP (Raster Image Processing) software is a vital component in printing technology. It converts the image into a format that can be processed by the printer hardware. Thus, it’s a proprietary element and totally depended on the printer hardware.
The printers that are thought to be generic, actually contain an embedded RIP software. They perform well under a wide range of conditions, but when compared to printers with a dedicated RIP software, the quality decreases. Keep in mind that there are no generic printers that perform well in all conditions. The printing performance and versatility converges half-way, thus influencing the print quality.
Another thing to pay attention to is the INK. Most people wrongly believe that all inks perform the same. However, this is not true. Different types and brands can vary when it comes to the result they provide. Inks are very vital, like their materials and firmware counterparts. There are various types of inks, but the most common ones will be covered here.
The types of inks are pigment-based and dye-based. The dye-based ink can further subdivided into water-based (aqueous) and solvent-based (example are alcohol-based) types. The pigment-based inks are commonly used in materials exposed to environmental changes, such as in billboards and signages. They are water-proof and hardly fade over time.
On the other hand, dye-based inks produce more vibrant and bright colors. They are most commonly soluble to water, and other solvents like alcohol, and acetone. Dye-based inks are commonly used in flexible media, such as vinyls, shirts, and other garments. They are currently identified as eco-friendly (eco-solvent) inks.
Ensuring the print quality always starts with the printer hardware selection. A properly selected printer influences the print quality. Aside from the hardware, the software or firmware aspect must also be considered. A proprietary RIP software is essential for achieving optimum print quality. The print media selection and quality also affects the print results. Use the proper media density in all printing jobs.
Lastly, use the appropriate types of ink for the intended media. For example, all outdoor applications must be printed with pigment-based inks, because they resist fading and discoloration better than any other ink types. They are impervious to UV damage and weathering. For flexible media, such as shirts and garments, use the optimum dye-based inks to ensure extensive print quality.
Commercial printing quality control starts and ends with the proper printer selection, image processing, media control, and proper ink selection. Never validate the print quality with a minimum acceptable criterion.