Making the Grade: Testing and characterization enhance the value and predictability of inkjet media.
By Nick Billow, Eastman Kodak Co. and Colin Martin, Encad;
DIGITAL OUTPUT MAGAZINE - JUNE, 2004
Courtesy NUR Microprinters
Do you know how long your banners and large format graphics will last? Probably not. Since large format inkjet printing became a market force in the 1990s, people have been printing projects, then crossing their fingers and hoping for the best. Inkjet prints were famous for fading in months, or even weeks, in outdoor applications.
The technology has made great strides over the last few years. Some of today’s large format inkjet products even rival photographic materials for longevity and durability. Thorough durability testing has become a common industry standard.
Passing the test
Generally speaking, each inkjet media product is evaluated by three classes of testing: technology assessment, compatibility testing and durability. Each new media undergoes an average of 1,000 hours of testing prior to commercial release.
Technology assessment defines paper characteristics such as thickness, caliper, basis weight, curl properties, whiteness, brightness and opacity. The testing also includes an assessment of image quality on the paper based on density, color gamut, bleed characteristics, uniformity of color and drying time.
In predicting the performance of inkjet media, it’s important to think in terms of a printing system. Each combination of media, printer, ink and software together comprises a printing system, and each system is evaluated independently. So a given type of inkjet media will be tested across a variety of printing systems, and its performance may vary from one system to the next.
Compatibility testing starts with a combination of printer and media, then examines other factors that might render them incompatible. Lamination is tested with different laminates in four categories, across a dozen printing systems. In total, there are hundreds of combinations.
Testing is designed to reproduce real-world circumstances. So the applications test includes printing, laminating and posting the product just as a customer would. And the images being printed mimic real-world applications, not just test targets.
Moreover, testing reaches beyond optimum conditions. If a customer might need to laminate an inkjet project an hour after printing it, in 80 percent humidity, the lab will test under those conditions. As a result there is rarely anything the customer would do that has not been tried. Problems that might occur in the field are identified quickly, and the media can be reformulated to address them.
Durability testing includes fade resistance in multiple test chambers that simulate different conditions such as fluorescent lighting, sunlight and outdoor environments. Temperature and humidity chambers are used to see if either variable changes the image, and to see how stable the product is after it is printed in extreme conditions.
The results of all this testing are twofold: First, better, longer-lasting inkjet media is produced. And second, it provides customers with comprehensive information and documentation about the inkjet media they are using. Armed with that data, inkjet users know what they should or shouldn’t do with a given type of media and what they can expect from it.
Another result of the exhaustive testing is a new set of software profiles developed for each type of media. With those profiles, users can optimize results with a range of printing systems.
Today, inkjet users can choose from an ever-changing, ever-improving family of media. Each time a new generation of printers is released, the opportunity to improve the whole printing system begins anew. And new media are developed on an ongoing basis to further raise the bar.
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