It used to be that press proofs, also called wet proofs, were the only way to ensure color fidelity and print accuracy prior to going to press. Today, with budget constraints and shorter times to market, publishers are turning to digital proofs. Say goodbye to tedious plate-making processes and different color printing to make up the wet proofs. It is now straight from the computer to the digital proofing machine, shortening the cycle time with less wastage and chemicals, and thus making the process a lot greener.
“There has been no new press-proofing machine or technology produced for more than 30 years, and those in production here in Hong Kong and China are essentially the same old version,” says Ken Kong, director of Jade Productions. “Dainippon Screen 123 and 124 are the two most commonly used on the production floors, and the 124 model is the last one before Dainippon stopped making these machines several years ago. Nowadays, if a client insists on seeing press proofs, we will usually run it through the printing press, which makes the cost even higher than using the proofing machine. But it does offer greater assurance in terms of quality and accuracy, since we use the actual production stock.”
And this is where digital proofing comes in. “We mostly use HP Indigo, which can print on a wide variety of substrates—and this is the biggest advantage,” says Kong, who uses Hong Kong–based Uniplus and its Shenzhen-based workshop BADC for prepress services. “It allows us to print on the same stock that is intended for mass production, as opposed to using the Epson printer, which mostly accepts only specialty paper. With the Indigo press, the challenge is to calibrate it as accurately as possible to simulate actual printing colors and quality.”
About 30 years ago, when children’s book publishers started printing in Hong Kong/China, the bulk of the color-separation work went to the major prepress company Bright Arts. It was the first supplier to advocate using rhodamine to substitute for magenta in order to get the clean bright red favored by the publishers. “A better result was later achieved by using 50% magenta plus 50% rhodamine to substitute for 100% magenta ink, and this became the standard application for proofing children’s books for many years,” Kong says.
Such ink substitution was tedious and costly in earlier iterations of the Indigo press. “But the new HP Indigo,” Kong says, “with seven ink stations—allowing for CMYK inks plus three more—has no problem adding rhodamine if our publishing client requires the digital proof to achieve, or match, the levels of colors and quality of a wet proof. In most cases, proofs produced by the basic four-color Indigo press are sufficient for publishers.”
At Imago, the project type determines the proofing system used. “Wet proofs are really the only option for duotones and special ink mixes,” says Howard Musk, Imago president and CEO. “We also use wet proofs for a lot for book jackets and covers, which often do not fit the digital system, and many of our clients like to see full-jacket proofs with all the finishing added. Digital proofing systems have come a long way, and for most applications, they are perfectly fine. Some are better than others, of course, and manufacturers continue to make improvements on how accurate the resulting proofs are compared to what can be achieved on a traditional production press.”
Imago currently employs a new Canon system that has the ability to use production papers and is very economical. “We find the system to be very accurate for coated Fogra standards 39 and 51, and it also works well for the newer uncoated Fogra 52 standard,” says Musk, who started offering Canon digital proofs through Imago’s partnership with Bright Arts in 2019.
Digital proofing on uncoated paper has always been a problem. “It is hard to mimic the ink dry-back and dot gains that you get with a production press that uses a variety of different papers,” Musk says. “The Canon digital proofing system offers a big improvement in this area. However, traditional wet proofs still have their place, especially if the total ink coverage of images is high, particularly with regard to black and cyan.”