When it comes to developing dotmeters, Centurfax has form – in a good way. Back in the late 1990s, when CTP was new, it was one of a brace of British firms, along with Laurie Mullaney Associates (LMA), that led the way in developing measuring instruments for plates.

Fast forward a dozen years and the two firms have joined forces to introduce a new dotmeter, which Centurfax sells as the EasyDot. It’s LMA’s hardware with Centurfax’s software and firmware.

The EasyDot is an easy-to-use device that enables you to measure dot percentage on plates. Line the measuring target up, press the case down, wait a second or so and there’s your reading. That’s it.

"Most users don’t want or need the more sophisticated features such as dot size, screen ruling and angle," says Paul Foster, managing director of UK reseller Ripware. "As long as you know your dot gain and as long as it’s consistent you, only need to take a couple of readings to know that your plates are OK."

Any plate with a visible image can be read, which means all processed plates and several no-process plates, including Presstek, Agfa’s Azura and Fuji’s Pro-V, are all suitable for the product. However, those that develop on press, such as Fuji’s Pro-T and the Kodak Thermal No-Process Plate, can’t be read.

Some rival devices claim that they can read the Fuji plates, with the aid of a special fluid to reveal the image – presumably, this would work in the same way for the EasyDot. As for those devices that claim to read the image prior to development, Foster questions how the user would find the location of the patches to read.

Added specifications

If you want access to more sophisticated tools than just dot value, then for a few hundred pounds more they’re yours along with the ability to integrate with a RIP calibration tool or a spreadsheet.

Foster knows his stuff about what users want, having sold 1,000 of the EasyDot’s predecessor’s the CCDot to UK printers. Centurfax sold the rights to the CCDot to X-Rite, which in time shifted its focus to its ICPlate product, based on a rival design from Viptronic, which it had acquired.

Not that there was anything wrong with the CCDot. Foster reckons at least half the machines he sold are still in regular use and he still gets approached by customers who want to get their machines calibrated or repaired.

"Units that are 10 or more years old are still working fine and if they are you wouldn’t want to change them," he says. But, with a design that is a dozen years old, it’s getting harder to source the components for repairs and it may get to a point where it’s more cost-effective to buy a new unit, rather than repeatedly patching up an old faithful.

Aside from replacements, there are also those wishing to buy their first dotmeters. Believe it or not, some firms in the UK are still making their first move to CTP and so purchasing there first dotmeter is a necessary move.

Prior to the digitisation of reproduction, including the adoption of CTP and ICC-based colour management, the industry was happy to measure the film made on imagesetters to control the imaging process from file to plate and the all important RIP curves. You got your dot gain right, you ran to density and that was good enough.

Fooling the eye

The principle of halftoning an image – regardless of whether it is AM or FM screened, is to fool the eye into seeing different tints depending on how much of the substrate is covered in ink. Massively oversimplified, if half the paper is covered (a 50% tint) then you get a mid-tone density.

In a simple example, some clever maths called the Murray/Davies and Yule-Nielson equations could use a density
reading and, based on knowing the film base or paper
density and the D max for the ink or film, you could calculate a dot percentage.

However, with a rough grained plate with a grey metallic tint and whatever colour of image bearing emulsion, it got more complicated. Therefore, when digital plates came along, just about the same time as digital cameras did, several clever firms, including Centurfax and LMA, saw the potential of using a very specialised camera to photograph the surface of the plate and analyse the actual area covered in dot, rather than determine a fudged reading from the density and some clever maths.

The need to control dot gain never disappeared and so the need to measure actual dots on plate remained. Even so, the adoption of thermal plates, and latterly no-process plates, meant many firms assumed it wasn’t necessary to keep tight control on the platemaking process. For Foster, that was never the case and now there are two compelling reasons to get back into the habit of measuring plates.

One is the adoption of ISO 12647-2, which is making a tight grip on your density and dot gain, or if you prefer the more modern term, tone value increase (TVI), a necessity. The other is the demand to be ever more efficient.

"With ISO 12647-2 you have got to check your plates," says Foster. "Although strictly speaking, you always did.

"The problem is that people don’t check anything and then, when there’s a problem on press, the first assumption is it’s the plates. The problem then is if you make a new set of plates and put them on only to find it hasn’t fixed the issue you’ve wasted time and money."

He reckons that an average problem can take around two hours to troubleshoot.

"When you ask a printer what two hours’ downtime on a press costs, that’s the ‘aha!’ moment, when they realise all it takes is a couple of jobs to get the cost of the EasyDot back," he says. "And that’s just your time, never mind the consequence of a bad job. The least that will set you back is a reprint, the most costly outcome could be to lose a client."

Budget concerns

Even so, the grand or so to buy the EasyDot can still be hard to come by. To overcome that, Foster is in talks with a finance firm to spread the cost over a couple of years, which takes the cost down to "a couple of quid per day", and well within any firm’s reach.

Centurfax’ other approach to meet the needs of the budget-conscious is the MicroDot, which was launched at Ipex in May. It uses an off-the-shelf digital microscope, which plugs into a PC, and uses Centurfax software on the computer to analyse the dots.

One of the target markets is inkjet CTP and the firm is talking to at least one plate supplier about an OEM deal. The MicroDot could be the key to the success of the inkjet CTP market argues Foster.

"Inkjet CTP is difficult to set up without a dotmeter and before the MicroDot the dotmeter was too expensive, now I think we’ve got the pricing right."

If you’re new to CTP, looking to get a better handle on your process control, or a faithful user of an older unit that has seen better days, Centurfax and Ripware have the gadgets to keep your plates in check.

Contact
Ripware 01483 578618 www.ripware.co.uk

Centurfax MicroDot

Aimed at budget-conscious users – especially those using inkjet printers to output plates – the MicroDot uses an off-the-shelf digital microscope to make the readings and is connected to a PC running Centurfax software.

Laurie Mullaney Associates ScreenReader

The ScreenReader can handle low-contrast materials, in particular digital screens for screenprint. It can also handle litho plates and LMA is working on low-contrast processless litho plates and flexo too.

Techkon SpectroPlate

Available in three versions: the Start model offers dot value, screen angle and frequency; the Expert version adds dot gain transfer curves, geometric analysis and can store 100 readings; and the All-Vision version is the Expert vision with the added ability to measure low-contrast processless plates.

Troika Systems LithoCam II

The basic LithoCam II Lite is the nearest alternative to the EasyDot with basic dot value reporting on film and plate, although it relies on a PC connection for power and processing. 

X-Rite iCPlate2

Measures standard plates, high-contrast processless plates and with a special cleaner, can read Fuji Pro-T. Based on the Viptronic's technology acquired by X-Rite, ICPlate2 is available in two versions the basic X and the XT.