Proofing: today's converter's can choose from a number of technologies in the quest for accurate contract proofs.
Not long ago, analog proofing materials were the only choice available. In the 1960s, printers were introduced to an overlay proofing product made by 3M, called Color Keys. "These would be individual process colors mounted on a clear polyester support and mounted together in register," says Bruce Sipiora, channel manager, North America, for DOD proofing systems, DuPont Imaging Technologies in Wilmington, DE. "It is used for layout, checking trap and the position of colors and maybe in some regard a very rough color guide."
In 1972, the printing world was introduced to DuPont Chromalin, "which was the first of the laminated one piece proof offerings. Initially, this analog proof was made from film positives, and later modified to be negative working," says Sipiora. In the early '90s, Chromalin was augmented with an additional negative-working product, DuPont Waterproof, which allowed for proofing directly onto the substrate. Proof offerings from other manufacturers quickly followed.
According to Pat O'Brien, president of Premier Sales Ltd., in Wakefield, RI, analog proofing is simply utilizing individual film negatives or positives "that carry the individual color information, using one of many proofing media to create a proof through a contact exposure process."
Although a long time has passed since analog proofing processes were first introduced to converters, many narrow web converters continue to make use of this technology. "I would think 80-90 percent of converters use analog, and those would be in the form of laser proofs, Color Keys or analog Waterproof, Matchprint, or something like that," says O'Brien.
While its use is widespread, analog proofers are not without limitations.
Analog proofers historically have been engineered to match offset printing. Consequently, dot gain is calculated according to offset standards.
"This has required flexo printers to accommodate these differences in their workflow, via the generation of an adjusted set of films, in order to have press production relate to the proof and have print predictive proofs available for their client," says Sipiora.
This is not a new challenge for the flexo narrow web converter. Those employing analog proofing systems have probably done so for awhile, fine tuning the process well enough to achieve good consistency with the final product. Still, others are feeling pressured, either by customers or by the industry as a whole, to move toward a digital workflow.
The advent of computer-to-plate platemaking technology has jump-started interest in digital proofing. Computer-to-plate platemaking technology eliminates the need for film, the key component needed to make an analog proof. While digital workflows do not currently claim the lion's share of proofing business, many see digital workflows, including computer-to-plate and digital proofing technology, as the direction in which the market is headed
"Digital proofing is now available. It will increasingly play a larger role in the future for a number of reasons: the potential for improved print quality, productivity, cycle time, and cost reduction," says Sipiora.
Inovar Packaging Group Inc., a converting company located in Arlington, TX, recently made the switch from analog DuPont Waterproof to DuPont Digital Waterproof. "That's just where the industry is going," says Russell Huff, plant manager. "A lot of our customers were starting to ask for remote proofing and pdf formats. Everything is generally going digital, so why not keep [proofs] in a digital format?"
Remote proofing refers to having multiple proofers all attuned to the same specifications. For instance, a large customer might have a proofer at its location, and the converter can set up a system where proofs can be directly printed at the customer's location. Pdf proofing, also known as soft proofing, is a method in which the customer receives a pdf proof over the computer, instead of a hard copy.
While there is controversy over soft proofing because of color management issues, it is still one service converter's can offer customers only if they employ digital workflows. That being said, good color management, communicating and matching color accurately and consistently, is critical to the digital proofing process. Without it, a proof cannot be considered reliable.
"The key to any system is good color management, and the key to good color management is to stabilize and standardize the printing press and monitor those conditions on a very regular basis. When things change, that has to be plugged back into the prepress profile of the press so the resulting color reproduction, whether it's on a proof or coming off the press, can be adjusted accordingly," says O'Brien.
While digital proofing is increasing in popularity, there is debate over two distinct technologies: digital inkjet and digital halftone.
There are several different technologies under the umbrella of digital inkjet. One is called drop on demand. "Essentially when a droplet of ink is required on the paper, it shoots a drop on the paper, and that's in the simplest form," says Patrick Floody, product marketing manager for proofing solutions, for Creo Americas Inc. in Billerica, MA.
"In drop on demand, as with most digital systems, there are a number of parts that are needed in order to make a complete system. You need the RIP, you need a RIPing platform, the paper, the inks, the output device and the profiles. They are all a function of how well you can print color," he says. According to Floody, a RIP translates file information and turns it into a set of instructions for the printer.
Creo Americas Inc. has created a drop on demand digital inkjet system called Creo Integris. Featuring ICC color management, the system combines the Integris Proof Controller, and qualified inks, media and inkjet printers to create color managed proofs. The proofing system costs between $14,700 and $18,800, and is one of the more economical proofing systems in the Creo line of proofers.
DuPont also manufactures proofers utilizing drop on demand technology. The Chromalin b2, a repeatable drop on demand proofing system, is engineered as a complete system, including a proof engine, CromaNet Color Management, inks and media. The company also offers CromaPro, which utilizes Epson or HP printers.
There are other types of inkjet proofing technologies available besides drop on demand. Creo also offers higher end proofers, such as the new Veris proofer. This proofer uses Multi-Drop Array inkjet imaging which produces a controlled stream of drops at 1500 x 1500 dpi.
DuPont manufactures Digital Waterproof proofers (known as Digital Chromalin in Europe.). This unit employs continuous flow inkjet print head technology. As the name implies, the droplets emerge from the print head on a continuous flow basis. It works with CromaNet Color Management, and uses DuPont Color Proofing inks and media.
Inkjet proofing is generally considered to be less expensive than halftone proofing, a technology that is discussed below.
"The major advantage [of inkjet proofing technology] is cost. Generally, the cost per page is a fraction of the digital halftone dot. Also in a lot of eases it can be faster. So speed and economy are two of the driving factors why people are considering inkjet," says Floody.
But many argue inkjet technology has a major drawback. The main discussion surrounding this type of proofing technology is the fact that it does not reproduce dots.
"Unlike analog proofing, conventional inkjet digital proofing does not employ halftone dots for deriving a color match. Inkjet color matching uses color management software to define an inkjet printer's color space; the output of that device is then directed, by this software, to conform to the color space of the printing press. With color management, a 'recipe' of ink droplets flow from the print head to render a colorimetric match," says Sipiora.
"When an inkjet platform is color managed, we're normally working with press characterizations. We use this information as the basis for color matching. This characterization defines net printed results and embodies all the elements that make up ink-on-substrate color results, such as density, dot gain, trapping performance, opacity and hue of inks, laydown sequence and print contrast," he says.
Whether or not the dot is important is a matter of opinion. Perhaps it comes down to tradition. "That was probably the biggest milestone I had to get over," says Huff of Inovar Packaging Group. "I've been so used to seeing a proof with a dot. When I went out to the pressroom floor I liked to see dot structure on a proof so I could compare it to what's actually being printed. But alter we got the system in, it was easy to get over."
Digital halftone proofing is another digital proofing technology on the market today. Like digital inkjet, there are a number of different technologies represented under the umbrella of digital halftone proofing.
One company that manufactures digital halftone proofers is Latran Technologies, located in Bedford, MA. The company's halftone technology works as follows:
"In Latran's case, with the Prediction, we use a patented process called Laser Ablation Transfer," says Kevin Hooper, marketing communications manager and business development manager--packaging. "We transfer pigmented inks by directly imaging or transferring to actual printing substrates. The real ink pigments are ablated to the substrate. By incorporating many other RIPs to the front end of our Prediction proofers, we can show actual halftone dots on the output."
One digital halftone proofing system Latran Technologies offers to narrow web converters is the semi-automatic Prediction 1420. The list price, including the imager, finisher, Harlequin RIP and starter kit, is $49,500. Creo Americas is another company that offers halftone proofers. One model is the Proofsetter Spectrum, a standalone proofer that uses SQUAREspot thermal imaging technology. The system promises dot-for-dot fidelity, with sharp, small dots. The unit sells for $140,000.
The main advantage of digital halftone technology is the ability to print halftone dots. The dots on a proof allow the print operator to "see what's going on by looking at the nature of the impression of the dots on the printed sheet versus how the proof is looking among other aspects of the proof to press comparison. He's got more to work with when he's troubleshooting matching the proof to press," says O'Brien.
Digital halftone technology is also considered to be a higher end process, producing proofs of higher quality. "The ultimate quality for proofing is the halftone dot," says Floody of Creo Americas.
Besides producing the dot, "digital halftone proofs give a truer representation of the file going to the plate," says Hooper. "If there are any file or screening abnormalities in the job, the Prediction will be able to show those. An inkjet, in many ways, does not have the ability to show those abnormalities."
Recently introduced digital halftone proofing technology has reduced the cost divide between digital inkjet and digital halftone. Because of the historically higher costs, however, converters using digital halftone proofers are typically in high end markets or in markets where customers are highly critical.
"It's really based on the end use requirements. 011 the one hand, for many high quality label buyers digital halftone proofs are most representative of their printed product due to the ability to proof on the substrate on which the production order will be printed. On the other hand, if you get into the corrugated business, some aspects of the folding carton market, flexible packaging, and some of the label guys, they don't need high quality halftone proofs. Their customers don't demand that, so they can go with a digital inkjet proof," says O'Brien.
No matter what the technology, digital proofing must breach several barriers before widespread implementation can be realized.
Like all fledgling technologies, more education is needed on the topic. "The knowledge base needs to be developed to support the digital workflow," says Sipiora.
Also, the investment involved is significant. Many converters have used analog proofs for years and have developed a successful routine. The cost involved in switching to a digital workflow, including digital proofers, may not be worth it until customer pressure demands it.
On the road to customer approval, some converters give clients a number of proofs to look over. There may be a layout proof, a color layout proof, a contract proof, and an on-press proof (if it can be called a proof at all). While a digital proof is considered a contract proof by many converters, some choose to use an off-press press proof, otherwise known as a wet proof, as their contract proof of choice.
J.M. Heaford, located in Manchester, England, manufactures the Narrow Web Drum Flexo Proof Press. "It's the same flexo printing process basically, and you use a single color at a time, and rather than having a multi-station printing press, you just have a single roll around which you wrap the substrate that's going to carry the image. Then you effectively print each color of the job one at a time onto the substrate that's wrapped around the roller," says Mike Heaford, managing director.
Heaford says that in the world of proofing, there is a place for both wet proofing and digital proofing. This is because he does not see a digital proof as a contract proof. "It's a proof of a computer file, not of the end print form."
A wet proofer provides a real print and also serves as a test of the manufacturing process. "Apart from providing a contract proof for plate makers, the drum flexo proof press can be used by a printer to take disruptive on-press customer approvals offline. It is also used in areas where digital proofing is felt to perform poorly, like with paper substrates, and in liability exposed printing, like pharmaceutical labels and bar codes," says Heaford.
The Narrow Web Drum Flexo Proof Press sells for $70,000 to $85,000, depending on the specification.
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|Publication:||Label & Narrow Web|
|Date:||Oct 1, 2003|
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