Software, hardware, systems and standards are making it easier than ever to ensure colour remains consistent across the board.
Managing colour is one of the most complex and challenging aspects of producing a quality sheetfed press run, whether traditional litho or digital. But the goal of colour management is simple: to ensure colour images reproduced by mechanical and digital media match their real-world sources – or deviate from them in controlled, consistent and reliable ways.
Colour management can’t guarantee perfect colour reproduction, but if done correctly it can produce results that are consistent across all media.
The
International Color Consortium (ICC) has defined a number of key concepts for the industry:
An open standard for a colour matching module (CMM) at the OS level.
Colour profiles for:
Devices, including device-link profiles that represent a complete colour transformation from source device to target device.
Working spaces or the colour spaces in which colour data is meant to be manipulated.
These are the building blocks for printing technologies around the world.
We’ve recently been to
drupa and seen what’s coming up for the industry. But casting our net more broadly, we found two exciting new developments for colour management and printing.
Exchange space for pure digital printing
A digital exchange space ICC profile has been developed to support workflows for pure digital printing, which arose from the necessity to use a digital printer’s full colour gamut rather than simulate a conventional printing press.
The ICC notes there are three ways to achieve this:
Create a printer-specific profile for the digital printer being used.
Use a conventional exchange colour space and colour gamut extension to fill the printer’s gamut.
Use an exchange colour space that’s larger than the printer’s and use gamut mapping to convert it to the printer’s colour space.
The third option is a purely digital workflow, and the ICC has created “a colour exchange space that is approximately the size of the
Perceptual Reference Medium Gamut”. This CMYK exchange space is intended to be used in the same way as conventional exchange colour spaces. Printers can download a
PRMG-based profile to evaluate this workflow.
Two images, one space
A new technology has emerged that has big implications for not only colour but also for printing currency, passports, identity cards, credit cards and other sensitive documents that need to be robust against counterfeiting. It’s a technology that gives us the ability to print two images in the one space, meaning an image and its colours change when rotated in space.
Using 2D inkjets printing onto metal, researchers at the
Ecole Polytechnique fédérale de Lausanne have printed images along lines on the metal sheet, which creates directional shadows when struck by light.
The technique doesn’t work on paper, however, as it diffuses light and therefore doesn’t cast shadows.
The team developed an algorithm to predict what image would show at different viewing angles, allowing the printer to produce a ‘core’ and a hidden image in exactly the same space.
Colour printing with invisible nano-ink
Printing has come a long way, but one aspect hasn’t changed much: making colour by mixing dyes. However, now researchers at ITMO University in Saint Petersburg have developed a
colourless ink for inkjet printers.
It works the same way as an octopus’s skin – by changing the ink’s nanostructure, it reflects light in different ways and so produces different colours. The team has used a colourless titanium-dioxide-based colloidal ink and they produce colours by varying the thickness of the ink on its substrate. They haven’t produced a good red yet, but it’s just a matter of time.
It goes without saying that quality is everything. And technology is driving us closer to greater precision in colour to meet ever-higher standards for our customers. It’s innovations like invisible nano-ink, printing two images in one space and a digital exchange space ICC profile that allow printers to push their businesses forward.
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