With improvements to front ends for digital presses is there still a need for a colour server? Nessan Cleary investigates.
Colour management has come a long way from the days when it was considered one of the black arts, mastered only by a few dedicated and well-paid magicians. Nowadays most solutions offer wizard-driven simplicity that the rest of us mere mortals should be able to easily cope with. Yet there are still some tricky issues that need to be negotiated.
The first port of call is the digital front end which will provide all the basics. However, there is also a number of colour servers on offer, prompting the question, do you really need one? EFI has provided its Fiery front end Rips for digital presses for years, and is well known for its colour management solutions.
Raimar kuhnen-Burger, product marketing manager for EFI, says that some customers have opted for third party colour servers in the past because the older Fiery server was not able to match two machines together, adding: ‘But it’s a lot easier now that the Colour Profiling Suite has been able to do this and the device link profiles are much more advanced.’
However, colour specialist Paul Sherfield, who runs the Missing Horse consultancy, says that although you can get good colour management from the standard front ends, dedicated colour servers do have a place particularly for CMYK to CMYK conversions. It’s a point echoed by most other experts we spoke to.
Bodoni 4CX
Phil Binks, sales director at Bodoni Systems, says that the main issue affecting digital presses is the inconsistency of colour, noting: ‘The colour can change throughout the run of a print job and so it seems to be quite unstable.’ Mr Binks says that this can also affect newer presses with inline colour controls.
Bodoni’s solution is a module within its PressSign 4.6 system. Mr Binks explains: ‘We have a functionality called 4CX which is a method of creating colour correction curves and we measure a defined range of colours in a colour bar that we have created and that allows us to concentrate on getting the grey scale output correct.’ He says that it might differ from ICC profiling but it does use the full colour gamut of the press, adding: ‘You get a good colour match on a digital device to something that you might have run on a litho press.’
Some Rips will allow you to apply the 4CX-generated curve but for those that don’t Bodoni sells AutoCurves, a module from its InkWise line, which can apply the 4CX curve directly to a PDF file at the prepress stage. Mr Binks also points out that it takes just a couple of minutes to generate and apply a correction curve in this way, far quicker than having to create an ICC profile from scratch.
Alwan Print Standardiser
French developer Alwan Color Expertise has developed a well-respected solution, Print Standardizer, which is distributed here in the UK by the Colour Engine. Mark Anderton, managing director of Colour Engine says that a colour server can take a printer to a different level: ‘It gives you the right separation in terms of GCR, which can give a better handling of neutrals.’ He says that the system works by applying something similar to a dot gain curve, adding: ‘That allows us to keep the grey balance.’
Alwan also has a second product, CMYK Optimiser, which has its own colour engine so that it can automatically apply the correction curves at the prepress stage. It can be tied together to Enfocus PitStop Server via Enfocus’ Switch system to give a fairly automated workflow with files being preflighted, then colour managed before sent to the Rip. He adds: ‘The other thing it does is give you full reporting to a standard, so that you can do conformance reporting and you can have live conformance information beside the press.’
CGS Oris Press Matcher
Another popular option that’s been around for a while is Oris Press Matcher from the German developer CGS, which is distributed in the UK by image2output. Matt Crowther, technical specialist with image2output, explains: ‘The standard front end is just based on ICC profiles which don’t give enough control over the black channel with UCR, GCR and so on.
The colour servers use the same colour management as proofing systems. It’s a CMYK to CMYK device link profile, so you can edit the profile, tweak the colours and achieve the Fogra 39 standard on the press with this software, which you can’t with the front end. It’s addressing the lack of precision on the digital front end itself.’
He adds: ‘When you start mixing and matching with different devices from different vendors then it becomes even more important that you are using the same colour management on all of them to get them to match. And if they are running on different front ends with different profiling technology then you will never get them the same. It’s quite a marked difference in colour between these machines and if you want to match a litho press then it becomes even more important.’
He says that Press Matcher is more than just a colour management tool as it also has some workflow features such as preflighting and archiving. It has a browser-based interface so it can be shared over the web.
It can also be used for soft proofing, providing you have a calibrated monitor and Adobe Acrobat. This can recognise if your system isn’t calibrated and still be used for content proofing.
Mr Crowther points out that other systems use an iterative process of constant measuring, adding: ‘The CGS is wizard driven so it’s very easy to use.’ There’s also an option for applying calibration to a file through hot folders. There’s a further ink saving option, useful if you are also using a litho or wide format device.
GMG ColorServer
The main competition to Press Matcher is GMG’s ColorServer, as both of these use device link profiles rather than ICC colour management. Simon Launder, technical sales manager at GMG, says that this approach allows for CMYK to CMYK transformations without having to go through the LAB colour space as with ICC profiles, adding: ‘This gives us the ability to control each individual primary we print. So if you had a slightly warm black I could edit that and take a bit of magenta out and that wouldn’t affect anything else as the colours are all independent of each other.’
A central idea in the GMG system is the golden master concept whereby each device is profiled to a GMG chart and can then be measured and compared back to its original profile. Mr Launder says that this approach takes into account things such as humidity and temperature change.
Mr Launder disagrees that working to ISO 12647 standard might limit the effective gamut of a digital device saying that the trick is to map colours from one space to another: ‘We might not get the numbers but we will get a visual match.’ He adds: ‘ISO 12647 works perfectly if you find a paper with no optical brighteners but if you deviate from that then ISO numbers go out of the window. Most customers want a visual match and something that can be calibrated back to a golden state.’
This system is mainly designed to work with process colours but will also include light cyan and light magenta, which are often used on wide format devices, but not N-colours, such as reds and greens. Mr Launder says: ‘We can map Pantone and spot colours to the colour space that the device can allow. We are not constrained by LAB so we can allow pure colours such as yellows.’
Ricoh Ready4Print
Ricoh sells a colour server to sit alongside its front end offerings, which it calls Ready4Print. The technology has been licensed from the Polish developer PuzzleFlow. There are three modules for creating the profiles, processing the files and validating the results. Essentially it uses device link profiles stored in hot folders to determine the correct colour for the job in hand.
Product manager Gareth Parker says: ‘The operator can drag and drop a job into the hot folder and it will match that against the target that you have already set up.’ He goes on to say that there’s more to using a colour server than just the colour management, adding: ‘The DFE is still very powerful and they still do a great job. The difference is that you are cutting down the steps required to get to an end result. With a colour server you are paying for ease of life and automation and the steps that you don’t have to go through. People don’t realise how much time they can save and how much profit they can lose on a job.’
It should be pointed out that most of the main prepress workflows, such as Kodak Prinergy, Fujifilm XMF, and Screen Trueflow/EquiosNet , also provide colour management. Ultimately it comes down to choosing where in your workflow you are going to place the colour management to get the best out of the digital press as well as what other devices and standards you have to match to. You can get perfectly good results from a standard front end, but a dedicated colour server can offer improved image quality and much faster calibrations, particularly if you are using multiple devices.
Konica Minolta goes wide gamut
Although some bureaux find they have to limit the colour gamut of their digital presses to match other devices, Konica Minolta has introduced a print engine specifically for brighter colours the new wide gamut bizhub Press 70hc, based on the latest print engine from the Press 7000 model but with special toners and profiles. It replaces the bizhub Pro 65hc model, which used the older Pro C6501 engine as a basis.
Pauline Brooks, group product manager for Konica Minolta, comments: ‘We have sold to photobook printers and commercial printers where they have wanted to differentiate themselves from the normal output of a digital machine. Also direct mail for variable data campaigns where you want vibrant colours as opposed to just the normal from a digital machine.’
Ash Pandya, Konica Minolta’s colour specialist, explains: ‘We are trying to simulate the RGB colour space, which is different to what CMYK can achieve. The toner is different to the other printers. They are still based around CMYK but it’s the toner itself that brings out the vividness. It reaches further out into the colour space than the conventional toners can. We are still using a very simple process with no extra colours.’
Which standard?
Most digital presses are capable of hitting a fairly large colour gamut, yet all too often printers have to sacrifice this in order to achieve consistent colour or to match colours to other print processes.
Mark Anderton says that the main thing is to choose a standard and then conform to that. However, he describes the Fogra 39L standard as a bit of a cop-out, saying: ‘It’s very generic. We find in the UK that lots of printers are printing to uncoated stock so there is a mismatch between the file that the uncoated stock wants and what it’s getting. Our colour server technology can adapt the file on the fly to get the perfect separation for an uncoated stock so we are not compromised.’
Gareth Parker says that not all customers necessarily have to hit a recognised standard such as Fogra 39L. He explains: ‘They can hit a standard that they are happy with and have agreed with their customers. It’s down to individual circumstances but if you can demonstrate that you can get consistent and totally credible results close to offset then you might not need to go to Fogra certification. It’s not always a necessity, it’s how people are being creative with the technology. But sometimes it has to be more scientific and numbers driven.’
However, there is some hope that the situation will improve. Raimar Kuhnen-Burger says there is a new digital standard being developed, which will become ISO 53011, and which has different parts for each of the digital technologies such as toner, production inkjet and wide format. However, as is always the case with developing standards, progress is slow.
Contact
Alwan Color Expertise: www.alwancolor.com
Bodoni: www.bodoni.co.uk
CGS: www.cgs.de
EFI: www.efi.com
GMG: www.gmgcolor.com
image2output: www.image2output.com
Konica Minolta: www.konicaminolta.co.uk
Missing Horse: www.missinghorsecons.co.uk
Ricoh: www.ricoh.co.uk
