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

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.

2023 promises an interesting ride for print in India

Indian Printer and Publisher founded in 1979 is the oldest B2B trade publication in the multi-platform and multi-channel IPPGroup. While the print and packaging industries have been resilient in the past 33 months since the pandemic lockdown of 25 March 2020, the commercial printing and newspaper industries have yet to recover their pre-Covid trajectory.

The fragmented commercial printing industry faces substantial challenges as does the newspaper industry. While digital short-run printing and the signage industry seem to be recovering a bit faster, ultimately their growth will also be moderated by the progress of the overall economy. On the other hand book printing exports are doing well but they too face several supply-chain and logistics challenges.

The price of publication papers including newsprint has been high in the past year while availability is diminished by several mills shutting down their publication paper and newsprint machines in the past four years. Indian paper mills are also exporting many types of paper and have raised prices for Indian printers. To some extent, this has helped in the recovery of the digital printing industry with its on-demand short-run and low-wastage paradigm.

Ultimately digital print and other digital channels 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. For instance, there is no alternative to a rise in textbook consumption but this segment will only reach normality in the next financial year beginning on 1 April 2023.

Thus while the new normal is a moving target and many commercial printers look to diversification, we believe that our target audiences may shift and change. Like them, we will also have to adapt with agility to keep up with their business and technical information needs.

Our 2023 media kit is ready, and it is the right time to take stock and reconnect with your potential markets and customers. Print is the glue for the growth of liberal education, new industry, and an emerging economy. We seek your participation in what promises to be an interesting ride.

– Naresh Khanna

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