ITC gravure unit (Chennai)
It is an enervating and costly proposition to proof a job in a gravure environment. To predict accurate results, unlike proofing with an Epson kit at offset units, gravure firms need to print proofs on a gravure press, which turns out to be quite expensive, as compared to four-colour proofing.
As a solution for this, the European Rotogravure (ER), Janoschka and GMG developed Pac.Space, a standard for gravure printing, which was launched at Drupa 2012.
ITC’s gravure division in Chennai, which relied on cylinder proofs so far, is the first user of Pac.Space standardisation and GMG’s proofing modules in India. The implementation was done by Percept Print Solutions.
Explaining the process, Percept’s Das, says, “What we did at ITC was standardisation of their pre-press as per the Pac.Space settings. This includes standardisation of consumables and fingerprinting their machine followed by outputting proofs with customised profiles.”
The Pac.Space standards colour settings are also implemented in the designing software such as Photoshop, Illustrator etc. “In this way, we simulate the gravure machine on an Epson proofer with a standard media via GMG software,” states Das.
At ITC, three substrates, namely, PET, BOPP and paper, were standardised based on the fingerprinting data.
Percept also standardised the ink dilutions at ITC. Prior to Pac.Space standards, ITC used in-house standards for matching colour. “We found issues in their gamut where magenta was printing like red. Since the Pac.Space standards were not revealed by then, there were difficulties in implementing the profiles,” adds Das.
With the Pac.Space launch, we had to adhere to a formula which specified the LAB values for primaries and CMYK solids. “ITC’s magenta dilutions did not match the Pac.Space values. This was resolved by conducting tests so that the dilutions met recommended LAB values. Later, we fingerprinted the gravure press, so that the colour was within the gamut. This is the reason we were able to reproduce it on an Epson proofer,” adds Das.
In case of standardisation in press, the ink dilutions are checked and standardised. It is a one-time process. If the ink supplier is changed, the draw-down of the ink needs to be re-calibrated. Adding to this, Das, explains, “If it matches the Pac.Space LAB, we define that dilution and standardise it and if it does not match, we will re-define the dilution and match it.”
Conclusion: Now, post implementation of Pac.Space and GMG proofing modules, ITC is able to achieve more than 90% closeness in the proofs as compared to the conventional cylinder proofs.
ITC had printed eight different jobs to confirm the accuracy, before Percept handed over the profiles for their production.
Das informs, “They are now avoiding cylinder proofing iterations and proofing at pre-press stage thereby saving 20% time.”
Currently ITC is simulating the colour for transparent films. In order to do this, they refer to the flexo chart. The flexo chart by GMG helps to identify the gamut of a machine. Das says, “We take the test runs of that particular chart on the machines with the different substrates they use. Then we have a defined value in our database; and then we analyse it and check how close they are and re-map it accordingly.”
The picture above shows an image, before GMG colour treatment and after GMG colour treatment. The ‘after’ image is passed through GMG colorserver-InkOptimizer. The “After” image shows the difference in the ink density in each separation (CMYK). The image achieved above is a combination of Colorserver and Inkoptimiser softwares. With, the help of the Colorserver, the image has been normalised to the required colour densities while preserving the integrity of the black channel. Then with the Inkoptimiser, a balance between C,M,Y,K channels is achieved. The integrity of the black channel is preserved. The quantity of CMY inks used is reduced, and the proportion of black ink simultaneously increased, while maintaining an identical colour impression. The result is a standardised and simplified colour management model that delivers consistent print results across multiple print processes and substrates.
Lokmat Media Group
The hitch at Lokmat: printing of four colour images with excess inks. The ink consumption was too high. When printed with excess inks, images become smudgy since newspapers can’t hold much ink TAC (total area coverage). The recommended IFRA TAC for newspapers is 240.
Das says, “We found the problem to be with the file they were using to print. The file they were using was for digital hoarding and not for newspapers.” Hence the TAC was high.
The solution that GMG offered Lokmat was to implement the GMG Colorserver Ink optimiser with profile editors.
“Initially, we standardised the entire workflow as per ISO 12647 standards, and pre-press as per ISO 39. This maintained linearity in plate-making and standardised the press as per IFRA 26 standards,” says Das.
“Next, we tweaked the machines to get the gamut closer to the ISO-39 standards. We focused on getting colour vibrancy and coolness of the colour here,” he adds.
“Then by using Colorserver and Inkoptimiser we optimised the colour separation and controlled the ink densities. The process is simple, we removed unwanted CMY’s and added it to K. This way it gave less ink densities on certain areas of the image.
This way colour was easy to achieve and the ink-water balance required was comparitively less and the gamut was close to the ISO-39 standards,” explains Das.
Lokmat’s press is now standardised to ISO-39 for a dot gain of 26 as recommended by IFRA. The densities that they follow now meet the IFRA LAB values.
Lokmat achieved a direct savings of 17-20% on ink consumption, post the implementation.
Neeraj Mahajan, vice president technical at Lokmat Media Group is testimony to the benefits offered by GMG installation. Mahajan says, “We are able to get predictable results, now. This is close to art-paper / calibrated monitor results because of the pre-press standardisation as well as the re-separation / gamut mapping happening within the GMG Colorserver.”
“Moreover the Inkoptimizer has removed the excess CMY to get a smoother and consistent result in press; less CMY means less water in those units which in turn means easy ink-water balance enables faster make-ready in production.”
“Furthermore the GMG’s Profile editor is a powerful and simple tool to create our own custom profiles and we have developed a well trained team to get the profiling done by means of the same.”
“On regard of saving part we have noted down justifiable saving as GMG claims against their product. This is beside the cost savings achieved by reducing the colour ink consumption with an ROI of less than six-months.”
Diadeis-Alia, one of the leading pre-media firms in India, specialises in package mock-ups. At Diadeis-Alia, they receive fingerprinted data from their customers. Their job is to do the profiling and provide the proofs. Therefore, for a ‘x’ digital file, a hardcopy will be shared, which has to match the ‘x’, since the data is fingerprinted. This is where GMG’s colour proof module with profile editor comes into picture. Alia Mumbai offers the solution to Durban and Dubai; inlcuding Mumbai.
Alia outsoruces their print requirement at 25 print sites in India. They receive the fingerprinted data at their Mumbai unit, scan the colour and set the profile and output it.
How did GMG manage the colour proof? GMG got a number of standard profiles like Pac.Space profiles, newspaper profiles, ISO-39 profiles, uncoated profiles etc. But no customer prints on a standard profile, a minor customisation is required at their end. Das says, “So what we do with Alia is fingerprint the test chart on the customer’s device, get it to Alia, scan it and rate it where in we get a gamut by uploading the LAB and then remap the Epson proofer accordingly. One profile takes two hours to process.
Otherwise, Alia would send their person for approval to 25 locations which is tedious. The press person would measure the LAB values with a colour calibrated spectrophotometer. Alia would take the LAB values and colour correct the image.
Testimonial from Nitin Apte, technical head, Diadeis-Alia: “We wanted to establish colour standards throughout the workflow, which is why we implemented GMG’s colourproof with profile editor.” “Now, post-GMG implementation, we are able to reduce cycle-time on the colour separations,” adds Apte. “We are now able to achieve predictable results results and get accurate colours.”
“With GMG at our setup in Vikhroli, we are able establish a connect with more printers who have GMG software at their press. It is big advantage to us now,” he adds.
Apart from this, Alia have plans to adopt GMG’s open colour proofing module in the near future.n
Matching textile colour
Percept Printing Solutions has played a major role in the textile printing market in Surat in offering its colour management solutions to the industry.
Surat as you know is the textile hub of India. It has an overall turnover of Rs 500 crore for textiles and fabrics. The major printing establishments across the city thrive on catalogue printings for the garment industry.
It has always been an issue with several print firms to match the colour of offset printed sheet with that of the textiles.
A photographer-based in Surat who works for the garment industry says says “Colour is an important parameter when it comes to sale of garments. When there is a mismatch between printed photograph and actual garment colour, the customers tend not to buy the garments.” Hence resulting in rejection of the job.
This bottleneck had to be sorted out. Some photographers and commercial printers in Surat approached Percept for a solution to this. Percept’s GMG proofing solutions was a boost to their businesses.
What Percept offered to these print firms are GMG ColourProof, ColourServer and InkOptimizer.
Using GMG colourproof, a photographer has to capture images of models with multiple garments and check the images on their colour calibrated monitors using GMG ColourProof. If there are any corrections, he can do so at the pre-press level itself until the proof matches the actual garment in terms of colour and details.
Photographers involved with the garment industry want their models to look flashy in the print version. So they prefer using coated papers, Natural Evolution, Mont blanc or Raster papers. These papers are the widely used substrates in the Surat market.
The challenge in printing on these papers, as said by a printer from Surat is reproducing exact colour and texture of the textile. “Our solution to this was playing with the colour altogether in the pre-press level with the help of GMG Colorserver and Inkoptimiser,” says Das.
In such a scenario, GMG Colorserver help the printer to convert incoming files with a GMG device link colour algorithm and get close colour results to the originals while outputting it in the presses on different paper types.
This partly solves the problem. Implementing GMG inkoptimiser along with the Colorserver ensures balance in the colour. GMG InkOptimizer uses the Gray Component Replacement (GCR) to change the separation of the image. It identifies the areas in which dots of all the four colours, CMYK are present. Then it replaces some of the CMY dots with black, thereby reducing the ink consumption.
GMG ink optimisers also ensure set-off elimination and quicker drying in many presses.
The Ahmedabad-based Shreedhar printers has implemented GMG Colorserver and Inkoptimiser along with proofing solutions to ensure their textile catalogue are printed with more colour efficiency. 70-80% of Shreedhar’s jobs are of textile catalogues. Minesh Patel, director, Shreedhar Printers says, “We need to match the textile colour with what the photographer gives and sometimes directly with the saree or textile. It is difficult to achieve without a standardised colour management solutions.”
“GMG Colorserver has given us a way to match colours exactly as per the requirements. Alongwith with this, Inkoptimiser has contributed to a 25% ink savings,” he adds.
“What GMG did with Shreedhar was standardise five to six papers which they use for textile catalogues and set the colour profile constant for that particular paper on the press. So when the image comes, the paper profile has to be selected on the press and output it,” explains Das.