Printability of Coated Papers with changes in Coating Binders

Technical article – testing Indian papers and paperboards

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Test image and result of evaluations of different coating binders on a variety of Indian papers and paperboards Images Kiran Prayagi
Test image and results of different coating binders on a variety of Indian paper and paperboards Images Kiran Prayagi

Different batches of coated papers of the same type and GSM from the same paper mill can show differences in printability with the changes in coating formulation. This work studies the papers and paperboards from a few paper and paperboard mills.

Different types of latex binders were tried in pre-coat and top-coat in paper manufacturing. A specially designed ‘print test forme’ was printed under production conditions in the same print run on a Heidelberg CD 102 sheetfed offset press using CtP plates and 4-color Huber Micro Inks Perfektion F series process inks. During the same run each type of paper was first printed with the correct ink-water balance and then with the dampening solution feed increased to 100% to study its effect on printability.

To realise the objectives and the research methods mentioned above a list of was drawn up as follows. A special test forme, see figure 1, was designed to study all the parameters.

Important parameters from the printers’ point of view –

Print density, Dot gain, Print contrast, Trapping in multicolor printing, Hue error, Grey error, Gloss, Lab values, Delta E on different papers, Mottling, and Set-off.

Important laboratory tests –

IGT dry pick, Stain length, Paper gloss, Print gloss, Delta gloss, Brightness, K & N, Set-off, Mottle index papers

Print Production Trials

Test image and result of evaluations of different coating binders on a variety of Indian paper and paperboards Images Kiran Prayagi
Test image and result of evaluations of different coating binders on a variety of Indian paper and paperboards
Images Kiran Prayagi

Laboratory Tests

Screen Shot 2022 Web700.29
Laboratory tests

Laboratory test parameters

Print performance inference through laboratory tests and production print trials

1. Print density trend in laboratory evaluation matches print production trials.

2. Density trend in porometric test is also reproduced in print production densities.

3. Back trap mottle (BTM) trend in laboratory is found to be in line with print mottle in print production.

4. Water interference mottle (WIM) in laboratory is found to be in line with print mottle rating of print production trials.

5. Set off density trend for SBR products are in line with mottling index for the production printed sheets. Lower set off values gives lower mottling tendencies.

Papers and paperboards for the investigations were kindly supplied by BILT, JK, ITC, NR Agarwal, Gayatri, Balakrishna mills. Huber Micro Inks supplied the inks and Jasmine Art Printers, Mumbai allowed the carrying out of all print production trials. Laboratory tests were conducted at Apcotex Industries, Mumbai.

The Covid-19 pandemic led to the country-wide lockdown on 25 March 2020. It will be two years tomorrow as I write this. What have we learned in this time? Maybe the meaning of resilience since small companies like us have had to rely on our resources and the forbearance of our employees as we have struggled to produce our trade platforms.

The print and packaging industries have been fortunate, although the commercial printing industry is still to recover. We have learned more about the digital transformation that affects commercial printing and packaging. Ultimately digital will help print grow in a country where we are still far behind in our paper and print consumption and where digital is a leapfrog technology that will only increase the demand for print in the foreseeable future.

Web analytics show that we now have readership in North America and Europe amongst the 90 countries where our five platforms reach. Our traffic which more than doubled in 2020, has at times gone up by another 50% in 2021. And advertising which had fallen to pieces in 2020 and 2021, has started its return since January 2022.

As the economy approaches real growth with unevenness and shortages a given, we are looking forward to the PrintPack India exhibition in Greater Noida. We are again appointed to produce the Show Daily on all five days of the show from 26 to 30 May 2022.

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