The Evolution of Digital Paper
Those of you who remember the original fax machines and the curly thermal paper output probably also remember the miracle of the “plain paper” fax. The “plain paper” was simply the same paper that was used in copiers – uncoated, white, 84 bright, 8-1/2 x 11. What was not obvious was that the “plain paper” was engineered for the technology and was not as “plain” as it appeared.
In my blog last month I talked a little bit about the evolution of digital paper and “plain” paper. This month, let’s dive in a bit deeper and talk about the different papers that have been engineered for the different digital printing technologies. Although the differences may not be visible to the naked eye, they are significant and will impact the quality of your print output. It may look “plain”, but looks can be deceiving!
3 technologies using “plain” paper are inkjet, dry toner, and liquid toner.
Because they use different inks, the requirements of the papers are different.
Since these inks are water based the papers need to be able to absorb the ink, but keep the colorants on the surface to get good ink density. Inks may be dye or pigment based and will respond differently to the paper surface. For that reason, it is important to make sure the paper you are purchasing is optimized for the appropriate type of ink. The surface treatments for inkjet inks are focused on improving ink density and color- to-color bleed – both will impact the sharpness and vibrancy of your image – as well as waterfastness, drying time and bleed through.
This technology, which many still think of as color copying, has shown significant enhancements in print quality. As toner particle sizes have gotten smaller, the level of detail that can be reproduced has become quite impressive. Additionally, many printers have the capability for clear, metallic and dimensional toners that allow for on press techniques that previously had to be done off machine. Smaller toner particles reproduce high-quality graphics on smooth surfaces. On very rough papers, the toner may fall into the “crevices” in the paper surface and result in non-uniform appearance. Papers for dry toner technology have optimized electrical properties (to improve transfer of the particles to the paper surface), moisture levels, and curl control. Dry toner is “melted” onto the paper surface, so the paper needs to be able to handle heat without deforming or curling. Because the toner is “melted”, it may give the print a glossy appearance.
Liquid toners are dispersed in oil that evaporates during the fusing process. The challenge with this technology has been ink adhesion on uncoated “plain” paper. A surface treatment is required to enhance ink adhesion and prevent flaking of the ink. Paper mills use various proprietary chemical additives to change the surface tension of the papers and get good bonding of the ink to the paper. Presses running liquid toner produce print quality that simulates offset with the flexibility of digital.
Unfortunately, there is not currently a “one-size-fits-all” uncoated paper for digital printing. The paper treatments are specific to the print technology. Many of the manufacturers have grades for the different printing presses, so you have options. Request print samples – on the substrate you are considering – before making your final decisions. Digital printing has come a long way and Domtar has a line of digital paper that can be just what you need for your next project. You can expect excellent print quality and image resolution with digital printing. Don’t let the selection of the “wrong” substrate diminish the quality of your output.