Offset Printing
New project started at SID
Monday 28. September 2020 - Saxon Institute for the Printing Industry develops new standard for offset printing on folding boxboard. Since September 1, 2020, intensive research has been underway on a new project at the Saxon Institute for the Printing Industry in Leipzig. The project, which has just been launched, is intended to develop a standard for the offset printing process on folding boxboard.
A large proportion of packaging consists of paper and board, eg folding cartons and blister packs. The top layer of corrugated board is also made from such material. There is a very large variety of materials in this area, covering the different strength requirements or processing variants. Another factor is that packaging made of these materials is positively evaluated in terms of its recyclability and is increasingly intended to replace plastics.
The ever wider application requires standardisation, which has not been universally available in this area so far. Brand manufacturers as clients for packaging production usually have their products printed at several production sites and attach great importance to identical print results. Usually different print products are assigned to one product, eg folding box artwork, labels, posters or displays for sales promotions. These are printed on different materials and sometimes using different printing processes, often supplemented by short-run products produced in digital printing. If the targets and tolerances are then not met by all parties involved, differences in colour reproduction are easy for the layperson to recognise with the naked eye, are very disruptive and have an impact on customer buying behaviour. If two packages are positioned next to each other on the shelf, where one appears slightly lighter, this is interpreted as faded and thus older. The customer will choose the packaging that has the stronger colouring.
The aim is therefore to find innovative ways to standardise the process for offset printing on folding boxboard. The properties that influence printability and colour reproduction are inadequately defined, which repeatedly confronts printers with unexpected problems when trying to print in a standardised manner. In particular, the roughness of the surface and the amount of optical brighteners in the coating sometimes differ greatly within several batches of the same material. The colour impression is changed again by a coating that is usually applied.
In addition, there is a wide range of ink series for printing folding boxboard that differ in terms of processing and properties (low migration, light fastness, rub resistance, etc.). In order to solve these problems, a printing company would have to carry out a separate profiling process for each ink-substrate combination. This would be extremely time-consuming and costly, which a print shop can only do in exceptional cases.
Instead, the aim is to develop practical characterisation data for folding cartonboard. It is important to group the substrates into material groups for which the same characterisation data can be used. An intelligent characterisation of the materials should enable them to be classified. A rapid test for the substrates is to be developed to enable a decision to be made on the selection and application of the appropriate profile in practice. This new test will be based on available information (e.g. technical data sheet) or on easily measurable values on the substrate, without the need for a proof on an offset press.
The parameters used to characterise the materials include various surface properties such as absorbency, roughness, the content of optical brightener or the degree of whiteness or colouring. For this purpose, an easy-to-use model is to be developed, which allows the allocation of unknown materials. This will avoid the need to maintain an excessive number of data sets for only slightly different output conditions.