Open Expanded Gamut Separations: Integrated Applications Deliver High-Quality Packaging

Spectral Prediction Tech

At the heart of this solution is spectral prediction technology that works from the converter’s spectral ink library, creating color accurate proofs and EG separations. Because this profiling is central to all color functionality within the solution, the entire process is simplified and more accurate than any previous method. The solution’s components are:

  • A tool that creates proofing and separation profiles that are dynamically delivered to the other components of the solution. With a dynamic profiling technology, printers can connect every part of the packaging production process together via a centralized database of spectral information. This spectral foundation allows color management of the entire printing process from end to end
  • A prepress application that provides the workspace to convert complete PDF and Illustrator documents into the EG color space. It also provides other critical prepress tools needed to prepare the EG color separations for printing. A native PDF prepress tool can circumvent the age-old problem that Adobe’s PDF libraries (and the applications that use them, including Photoshop, Illustrator and InDesign) cannot represent a process build or overprint containing more than four channels
  • A Photoshop plug-in that provides EG tools for images. If done correctly, it automates and simplifies many of the complex manual workarounds commonly used by Photoshop operators in existing EG workflows, to expand the color gamut of continuous tone images
  • Because of the need to assure the brand owner’s approval of final artwork, a contract proofing application completes the solution that is further extended within this complete EG solution

The individual tools are all available. The key lies in the integration between them. When a tight collaboration between these tools is possible, it can overcome the limitations of earlier production methods and put EG technology in the hands of packaging printers worldwide.

A good prepress application will display an accurate and quick view of the label and packaging design before and after conversion, while eliminating errors by highlighting risk areas. It will maintain the ability to edit the design as well.

Dynamic profile generation is beneficial for proofing applications, but it’s a real game-changer when applied to package design at the beginning of the prepress process. A prepress application can map spot colors to tint builds or color recipes, but by connecting dynamic profiling it becomes a powerful tool to easily and quickly convert package designs, created with numerous spot colors, to use EG process separations. The result is the ability to produce better quality with fewer plates, inks, printing stations and less makeready.

How It Works

Of course, no matter the process, there is still the upfront work of characterizing the press, to assure controlled and repeatable conditions, no matter the inks, register and press configuration (such as ink sequence or anilox). Multicolor test prints are required to determine L*a*b* values, dot gain and screening angles—and they must be measured and evaluated. This helps the printer to determine its own in-house standard of press, substrate and ink sequence.

Step One

Dynamic profiling with compliance to all published and in-house printing standards provides the way to generate a predictive profile, based on a large database of historical printing information. This can deliver much fewer measurements or minimal fingerprint data compared to other solutions (typically 30 patches, but sometimes as few as one patch, which can be printed in the trim area of production jobs instead of requiring a separate pressrun just for fingerprinting).

This allows a new profile to be generated, on the fly, for each set of printing conditions and ink sets from the pressroom. This is applied by the prepress package to convert the huge number of spot colors used by packaging designers into EG separations. Thus, it guarantees output quality regardless of the specific set of EG printing inks that will be used for a job.

“…using expanded gamut for conventional flexo printing allows for repeatable flexibility in hybrid digital and conventional production environments.”

The Ryerson report mentions that today, in EG printing, there is no standard or specification for the test chart, so vendors develop their own proprietary charts and patch values. The number of patches in the chart is of relevance to the real estate on printing systems and measuring instruments. The number of patches can vary greatly, from a selection of single patches, a ministrip of up to 30, a full chart similar to IT8/7.4 or ECI2002, to many times that number.

You can produce a model with any colors to minimize fingerprinting. A really good profiling solution will have a spectral algorithm that can predict in-between steps left uncharacterized by limited charts. Using spectral data, they are able to predict tonality through the range, through the interaction of other overprinting tints. Using an efficient profiling application, you will not have to print every situation to predict results. Both proofing and separating can be done from the same dataset. It will also accurately predict overprints. Using a mini-strip can further improve and adapt to dependencies and account for different substrates and colorants.

Step Two

The prepress software package is used to easily separate complex PDF or Adobe Illustrator files into any combination of EG separations, ranging from two to 10+ colors. It must also re-separate any channel into custom spot colors or other non-standard EG printing variants, like substitution of line colors for CMYK colors, and a myriad of other separation possibilities that improve profits and quality across the supply chain.

Professional prepress editors like PACKZ link directly to GMG OpenColor to show the conversions from spot colors to EG process colors as well as the visual error or Delta E introduced by the conversion, so the color conversions can be performed by the prepress operator.

This overcomes the 4-color limitation that affects Adobe-based products. If a solution depends on an Adobe application, many developers have created complex workarounds to overcome this limitation, such as producing multiple 4-color fingerprints, then combining them together to create a single EG profile. However, these workarounds add time and cost to an already complex process.

Without this limitation, color models are flexible and no longer limited to CMYKOGV, for example. Printers can select inks based on what colors can be reproduced best; in other words, what part of the gamut is best to expand to match a particular spot color.

A good prepress application will also display an accurate and quick view of the label and packaging design before and after conversion, while eliminating errors by highlighting risk areas. It will also maintain the ability to edit the design, analyzing and fixing layers—finding tiny text, objects and strokes where flat color ink mixes are required.