How far off are we and what do we still need to do?
Right first time in packaging printing
von Ansgar Wessendorf,
“It’s a great feeling when passing for print to have a first or second pull in your hand and to sign it off with a clear conscience”, declared Eva Jüde-Loeffler in an interview, that she gave at the 4th Packaging Printing Expert Meeting. “Unfortunately, I’ve learned from many years of practical experience that things don’t always go so smoothly.”
In my experience, the fewest problems in the production of folding boxes arise in offset printing. This is primarily due to the lack of complexity in the separations, which might, for example consist of 4C plus solid spot colours, as well as the application of current ISO/PSO standards and optical brighteners”, declared the colour management and proofing expert.
“Defined and detailed specifications for four colour process printing in the packaging segment are now widely known and applied in production. The challenge for the future is to extend this as far as possible to the standardized handling of spot colours.“
The qualitative comparability of production technologies for the economically viable production of packaging is important if potential printing methods are to be interchangeable and for getting it right first time in ongoing production. This would then allow short, preliminary runs to be digitally or flexo printed and then the subsequent long run to be flexo or gravure printing.
What’s more, narrow or medium width inline hybrid presses are increasingly being used for the production of high quality packaging in a single pass. However, this makes getting it right first time really challenging because modular presses can be configured flexibly to combine conventional and digital printing methods together with various finishing units (coating, embossing, die cutting, etc.).
Making clear what can be done Besides good technical preparation, the first thing to do is to reach an agreement with the customer about expectations, references and tolerance ranges. In order to head off disappointment right from the outset, Eva Jüde-Loeffler stressed the importance of close and open communication with the customer and all those involved in the process. Above all, it is a case of explaining what is possible and where the technical limits lie for the reproduction of a packaging motif.
This in turn depends on the future requirements for the piece of packaging in question, the printing method to be used (forme, press), the type of substrate, the ink system as well as the downstream finishing steps. Given the technical complexity of packaging printing, the specialist expertise of the prepress service provider and the printer are crucially important.
What does right first time mean? What precisely does the phrase, “Right first time”, which is being used more and more often in packaging printing, mean? For the prepress service provider and the plate maker it means guaranteeing a match between proof and print for every new and repeat job.
For the printer, the proof and print must match and the technical requirements for good printing behaviour must be met without lengthy makeready times for each job. For the final customer or branded goods manufacturer (agency), getting it right first time means fulfilling the colour and technical expectations of the new packaging design from the first proof off the production press, whilst at the same time meeting the production process deadlines.
Passing for print Anyone who works in the packaging printing industry is well aware of the practical difficulties associated with this.
According to Eva Jüde-Loeffler, it is far from unusual for a customer to pull a reference specimen out of a pocket when passing for print and ask for a “few last minute minor corrections” to be made. Matching the printed specimen to the colours of the proof or the reference specimen on the press in the presence of the customer takes hours and is only achieved with great difficulty or not at all, because one is already at or beyond the limit of the portrayable colour space. It is also important not to underestimate the costs of passing for print given hourly press rates, the use of materials, staff and organization (for example, travel, meal and hotel costs.
Consequently, the conditions for passing for print need to be precisely laid down in advance, which means defining the viewing conditions for checking the colour of the reference and printed specimen (ISO 3664:2009) together with the conditions for their quantitative checking (colour measurement: D50/2° observer/MO (M1), density measurement and colour difference formula. There also needs to be a clear agreement with the customer about which references should be used when passing for print. On top of which the production printing conditions must also be clearly defined.
What is meant by a printing condition? These are the set of technical parameters that together form the fingerprint together with an understanding of them:
Straight or reverse printing
Type and properties of the forme (including production parameters: RIP, laser and exposure settings, engraving parameters, angle)
Other process specific parameters such as adhesive mounting tape, blanket, anilox rollers and printing pressure.
The “5P rule”
Eva Jüde-Loeffler’s definition of the phrase right first time is that the first printed specimen from the press perfectly matches the expectations of the final customer – even in the case of the first print of a new packaging design. In order to be sure of getting it right first time when passing for print on the press it is important to remember the “5P rule”: Perfect Preparation Prevents Poor Performance. Besides good technical preparation, what this entails is agreeing with the customer in advance what the expectations, references and tolerances are for a first print. The complexity of packaging printing makes this a difficult task.
Printing conditions and passing for print The more complex the printing conditions, the more difficult passing for print:
Simple printing conditions: 4C colour set + solid spot colour + simple screened spot colour (SC), purely SC jobs without superimposed printing
Standard printing conditions: 4C colour set + solid spot colour and complex screened SC
Difficult printing conditions: 4C colour set + superimposed printing of screened spot colour
Critical printing conditions: Exclusively superimposed printing of spot colours
Innoform: a portrait
Innoform consists of two sister companies: Innoform GmbH (testing services) in Oldenburg and Innoform Coaching GbR in Hasbergen near Osnabrück/Germany. The testing services company operates a laboratory and offers film testing services. These range from measuring permeation through various material analyses to mechanical, thermal and legal tests.Innoform Coaching organizes meeting, seminars and workshops, as well as the Inno-Meeting, an annual event for the DACH packaging film industry. Every November it also stages the major Packaging Printing Expert Meeting in Osnabrück and in 2018 this addressed a hot topic in packaging printing: “Rihgt First time” . Through its varied range of communication channels, Innoform Coaching acts as a platform for experts in the field of flexible packaging.
Source: This article is based on the talk, “Right first time when passing for print – does it work?”, given by Eva Jüde-Loeffler at the Innoform Packaging Printing Expert Meeting in Osnabrück.