In 1999, a survey among 50 leading international web offset printing companies (90 percent heatset, 10 percent newspaper) within a framework of the “Web Offset Champion Group” initiative resulted in potential improvements in:

• makeready waste (98 percent)

• makeready time (91 percent)

• production waste (90 percent)

• constant print quality (81 percent)

• press set-up and operation (73 percent).

We see the trends of the future in, among other things, color measurement and color control and press adjustment (diagnostic systems for the analysis of defects in the printing process).

A comparison between manual and automated makeready procedures for multicolor print jobs and shows that times are greatly reduced with respect to ink presetting and color adjustment if automatic makeready is used. It is in these areas that we may expect an improvement in the systems studied.

Technological demands

Several manual measuring systems are already in use in newspaper printing. A disadvantage of this type of system is that the time of measurement is chosen subjectively, and errors that build up gradually or spontaneous changes are not recorded until another measurement is taken.

Closed-loop control, on the other hand, permanently carries out inline measurements automatically. Closed-loop systems for web offset printing that are currently available are used mainly in commercial printing.

In order to use such measuring systems in newspapers the following aspects must be taken into account.

1. Newspaper printing works with multi-web operation and variable web guidance. This would mean multiple use of measuring heads (one measuring head each for the front and back of the web).

In order to keep capital investment within limits, the system should be of modular design and in its first phase allow measurement of the economically most important webs (advertisements). It should be located as near as possible to the print location.

In order to implement an effective control system, we must take into account not only the time for the web to move from the printing unit to the measuring location but also the time to analyze the measurement and calculate the controlled variable as well as the time to complete the adjustment on the inking unit.

2. Ink systems with zonal adjustment require measurement across the width of the web. In scanning systems the time delays between measurements of the same particular measuring patch are dependent on the width of the web (commercially available systems measure in one direction, the measuring head is returned to position in the opposite direction). Individual measurements form a poor basis for control.

The result could be unnecessary corrections, which could possibly destabilize control. Therefore, several measurements of the measuring patches should be made and the average taken. The start-up process requires different strategies to the production run.

The rate of measurement must be adjusted to the type of control. Newspaper printing presses have short inking units with short reaction times (depending on the color combination).

It is open to question as to how many measurements are required to implement this in the control of a newspaper printing press. No conclusions could be drawn in this respect within the scope of this project.

Shortening the time between measurements, which is important at high speeds and the short reaction times of newspaper printing inking units, could be achieved by positioning more measuring heads on one side of the web, reducing the number of measuring points or the number of measurements per measuring patch to be analyzed before making an adjustment.

3. The measuring patches should be as inconspicuous as possible so that incorporating them into the layout creates few problems.

Control elements are regularly printed on the weather or TV listings page of the following Swiss newspapers: Aargauer Zeitung, Berner Zeitung, Bieler Tagblatt, Le Matin, St. Gallen Tagblatt, and Tagesanzeiger.

For example, 80 percent of Swedish newspapers work with gray balance elements. This leads to uniformity of print conditions and gives the advertiser the greatest possible color consistency.

Measurement in the image would make measuring patches redundant. However, this is not yet available in the field of web printing. Web monitoring systems of an appropriate configuration represent the first step.

4. The measuring system should be suitable for new installations and retrofitting to existing web presses.

5. Although tolerances are greater in newspaper printing than in the commercial printing sector (DIN ISO 12647-2) the tolerance regulations of commercial printing must be taken into account with respect to semi-commercial filler production and heatset-coldset hybrid technologies.

Existing control systems require that ink film thicknesses can be adjusted zonally. This cannot be done on anilox presses. Nevertheless, offline measuring systems are available for quality documentation.

Existing standards should be accounted for (e.g. measurement geometry) in the design of measuring systems.

Economic requirements

The economic viability of investing in closed loop or open loop color control systems cannot be universally determined, since there are too many parameters as a result of individual production conditions.

Potential for savings are:

1. Reduction in waste in makeready of colored pages. However, the contribution to saving on paper costs is difficult to determine, since usually there are a number of other causes leading to waste when setting up the press, particularly with register adjustments. Whether a faster good color adjustment does in fact lead to less waste depends therefore on whether color adjustment actually represents the longest adjustment process for the particular job.

2. Reducing waste during the run. In many cases of production the run is quite stable, sudden color fading is very rare and generally goes hand in hand with a malfunction on the press that would occur anyway.

Hence, color control systems will exclude only such cases in a traditional production run where a continuous color drift is not noticed by the printer. It is indeed difficult to judge whether and how many cases would lead to waste being generated. In the majority of cases in practice, even poor quality can be sold.

3. Saving in production time is directly linked to reduction in waste.

4. Reduction in the cost of proofs. If no ok proof were required for proofing huge savings could be achieved not only in the materials but also in making the whole process step redundant. It is true that the proof is defined not only by the press proof but also is mainly prepared in prepress anyway in order to qualify the prepress result and partly as evidence to show the customer. Therefore, it is difficult to quantify in how many cases the proof can actually be dispensed with and when a proof should be produced for the benefit of the customer independent of the print.

5. Increase in quality. We can assume that print quality will be more consistent and better across the run. It is true that it is difficult to judge whether a higher price can be commanded for advertisements or whether a customer decides on an advertisement on the basis of these quality aspects. It is open to question whether and what proportion of complaint costs can actually be avoided. But on the other hand, some newspapers reported that as soon as they document their quality, the number of complaints by advertisers that had to be accepted were reduced drastically.

6. A reduction in personnel is not directly possible since color control and adjustment is an integral working procedure for the printer, which would not be reduced by filtering them out.

It is indeed not debatable that the workload of a printer is reduced by color control and by organizing work more sensibly this benefit could be made use of elsewhere. If we accept that a color control system will reduce the printer’s workload by 25 percent, this effect would be useful if other organizational and technical measures allowed a further reduction so that one person could be saved.

The following costs are to be expected:

7. Capital investment and running service and repair costs. These costs can be estimated quite reliably according to the number of ribbons the press is equipped with: 250,000 euros plus approximately 3 to 5 percent annual service costs.

8. Additional paper costs due to test elements. It would be rare to use wider paper webs and/or cut off edges in an additional subsequent operation, in order to be able to position the necessary test elements. The preference is to try to integrate these elements as inconspicuously as possible into the layout and sell them together with the newspaper. Of course a loss of advertising space is very rarely acceptable.

In total, it can be seen that there will always be costs associated with the opportunity of making savings, which can only be estimated very roughly.

As an example to illustrate the effect we can apply the savings only to personnel costs and assume that there are no measurable effects in waste, production time as well as costs associated with proofing and quality but a reduction in workload of 25 percent for one printer.

Estimating personnel costs to be 75,000 euros, the 250,000 euro capital investment cost would be amortized only after 13 years. If, however, the person is calculated directly (because the manpower saving had been prepared for through other measures) we reach a more realistic figure of a good three years.

Hence, when making a purely economic decision, color control systems for today’s practical conditions are still too expensive in most cases. Investing in them today appears to make sense only in a situation where there are enough personnel to cope with the workload and where savings in personnel can be achieved through the additional reduction in workload associated with the introduction of color control.