Organizing Printing Trials
By Pulp & Paper Canada
By Pulp & Paper Canada
The scope of this article is to provide guidelines for organizing printing trials for major strategic product development trials, major competitive benchmarking trials, evaluation of changes in mill m…
The scope of this article is to provide guidelines for organizing printing trials for major strategic product development trials, major competitive benchmarking trials, evaluation of changes in mill materials or operations and investigation of major customer complaints.
Before starting to plan the trial, an overall definition of the project is needed. Why are we doing the press trial? What are we looking for? What do we want to report? Where do we want it printed to get the results we want? The size of the project must also be defined. Some of the factors that must be considered are the number of samples to be tested, the quantity of sample to be tested to obtain reliable results, press time availability and the resources available for testing and evaluation. Money is the main factor that will control the size of the project. This will separate the “need to have” from the “nice to have” and keep the project to manageable proportions.
In the case of manufacturing trials, substantial lead time is needed. Internal sales are usually the best candidates to track mill trial paper for you. For trial papers, sheet or roll dimensions required must be specified and the paper must be properly packaged and very clearly identified before shipping samples to the printer.
Planning the press trial
The responsibility for planning the trial should be assigned to one person such as someone from the mill, technical service, sales or marketing. Prepare a draft plan and present it to your internal customers to make sure they are on board. Revise the plan if necessary and present it again. It is important to do this right to avoid later grief.
Decide who will do the printing. Set up an appropriate print test pattern for the information you are trying to get. Do not use someone else’s pattern just because it looks good; it may not be appropriate for your needs. To plan the trial properly and avoid unexpected surprises later, it is necessary to do a detailed time estimate to establish the duration of the trial and the amount of press time required. Make certain that your trial fits in the available time slot. Prepare a write-up of the trial with press crew instructions, a sample list and proposed running order, a list of measurements and samples to be taken, a list of who is responsible for the different tasks, and instructions on the disposal or return of printed and unprinted paper. To optimize your press time, you must determine how many of your people must be present to carry out the extra work required. The recommended minimum for Rochester Institute of Technology type trials is three people.
Running the press trial
Start of the trial: Take a few minutes to meet with the press crew to go over the details of the trial. Explain the importance of keeping the samples properly identified. Otherwise, the whole trial is lost if a proper numbering system is not kept up.
Confirm the sample inventory against the master list and check the samples for transportation or handling damage. Write the run number sequence on each sample carton or roll and organize the samples in running order to avoid delays later. Check with the press crew what areas are available to you and lay out appropriate work areas for sample collection/packaging, data recording, testing etc.
Sampling during the trial: Samples required are white (unprinted) paper, printed paper and tape pulls showing blanket contamination. For wood containing grades a lint collector [1,2] (Domtar Lint Collector) is valuable for collecting lint build-up from the blanket. Ink and fountain etch samples should also be taken.
Make sure that you bring along the packaging material needed for your samples such as envelopes, plastic bags, labels, plastic/mylar film for tape pulls, ink cans etc.
Return of trial samples: Package your samples for shipping as the trial proceeds, building up cartons on pallets ready for wrapping, strapping and shipping. It’s advisable to bring along shipping destination labels to put on the boxes or skids to ensure the correct address and prompt return of the samples.
Wrapping up the final details: When the invoice is received, check its accuracy against the purchase order estimates and notify the printer of any errors. Finally, follow up with accounting to make sure the bills are paid. This will ensure that the printer will be happy to entertain you for another trial in the future.
Print quality evaluation
Visual: Since the quality of a print job is accepted or rejected by visual assessment, it is extremely important to evaluate the samples by some means of visual ranking. If the number of samples is not too large (16 maximum) a method such as All-Pairs Ranking [3-5] should be used. For a large number of samples a Rangefinder Sorting [3-5] is useful for the initial sorting into categories. At this point a more detailed evaluation of a subset can be done using the more precise All-Pairs Ranking method.
Other appropriate visual evaluation methods may also be used.
Instrumental: Instrumental printing tests that should be done are print density, paper gloss, print gloss and print-through. Any other printing or physical testing deemed necessary may also be done.
It is important that a brief, concise summary of the results be presented to key persons as quickly as possible. Ensure that you have answered the question(s) of the Project Definition. A full report with all details can be issued at a later time. Any written report should be kept simple and short.
1. HEINTZE, H.U., RAVARY, R.E. An economic means to measure and characterize lint, Pulp Paper Can 95(6) T237-40, June 1994.
2. HEINTZE, H.U. Producer develops simple lint test, Newsprint Facts Vol. 25 No. 2 1981, Published by Newsprint Information Committee, New York, NY.
3. KENDALL, M.G. Rank Correlation Methods, Hafner Publishing Co. New York, NY (1955).
4. TORGERSON, W.S. Theory and Methods of Scaling, John Wiley & Sons Inc. (1965).
5. RUTLAND, D.F. How to rank samples for print quality, 80th Annual Meeting, TS, CPPA, Montreal, QC, 1994.
Rene Ravary is with the Domtar Innovation Centre, Senneville, QC. This is a report prepared by the Printing and Graphic Arts Committee of the Pulp and Paper Technical Association of Canada. These reports appear periodically in PULP & PAPER CANADA.