Graphic Arts Magazine May 2018 | Page 20

Feature PDF gets a unifying update Pat McGrew Three cool things you want to know about PDF 2.0 When Adobe’s Portable Document Format (PDF) burst onto the scene in the summer of 1993 it was the Adobe response to a gap in the market: it was very hard to share files across MAC, Windows and Unix environments. From its launch in June of 1993 through the last 25 years of updates, PDF evolved from a simple display format to a comprehensive platform for printing, viewing, archiving, and file sharing. By 2008 Adobe had released PDF to the care of the Inter- national Organization for Standardization (ISO), which codified it as ISO 32000-1. While there have been updates over the last decade, it wasn’t until July, 2017 that PDF 2.0 was released, responding again to gaps. For many printers the introduction of PDF 2.0 will have little impact on the day-to-day work. It will take some time for DFE and RIP vendors to catch up to the feature extensions, and on the emitter side it may take time for design products to catch up. While many of the features of PDF 2.0 existed in the wide array of PDF standards, from PDF X-1 to PDF-UA, PDF 2.0 unifies the standard. To prepare for the options opened by PDF 2.0, let’s look at the following three areas. With page-level output profiles, you can assign specific profiles for different paper stocks and different presses. 20 | May 2018 | GRAPHIC ARTS MAGAZINE File Preparation Many print projects call for producing books, magazines, manuals and marketing collateral using different paper stocks and even different print devices, leaving production teams trying to balance colour without the aid of ICC profiles built for the output environment. In PDF 2.0 this gets easier with support for page-level output profiles. They add a new layer of granularity to how you associate colour profiles. Now you can assign specific profiles to allow for different paper stocks and different presses. This is a huge help to companies running offset, inkjet and toner devices, and mixing pages to create hybrid final products. Similarly, PDF 2.0 now allows for the output intent of an International Color Consortium (ICC) profile to be kept separately from the PDF data structures, which means that the ICC profile can be referenced using a URL. If you print graphic work that uses large black areas or features shadows, you will want to investigate the changes to object-level Black Point Compensation (BPC). PDF 2.0 expands BPC control when converting from larger to smaller colour spaces. Designers may remember when BPC con- trol was added to Adobe Photoshop at release 5 to create adjustments between the output device capabilities and the black in the file. An ICC whitepaper called Black-point compensation: theory and application (http://www.color.org/WP40-Black_Point_Com- pensation_2010-07-27.pdf ) describes how using this technique can render more detail in shadows. For prepress teams it is important to remember that Black Point Compen- sation does not apply to the absolute colourimetric rendering intent, where the goal is the exact reproduction of all colours within the gamut of the output device. There is some great news for printers who specialize in packaging, industrial printing or textile printing There is some great news for printers who specialize in packaging, industrial printing or textile printing. PDF 2.0 unlocks the option to use spectrally defined colour to pro- vide an accurate way to emulate spot colours both for proofing and for final print production. Using spectral values is common in packaging printing where the order in which the inks are printed, the dot gain, and screening may vary based on the substrates. Using the new feature requires that spectral data be added graphicartsmag.com