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Computer-to-Plate Goes Green
Environmental considerations have never played such an
important role in CTP. Tony King takes a look at the latest
products and asks which is the greenest of them all?
Computer-to-plate has moved a long way
in terms of affordability, performance and reliability since
the early days. Plate technology has advanced to the point
where printers can choose between traditional CTP systems
that use chemical development and new chemistry-free
technologies. This article looks at the latest
chemistry-free systems, the different technologies that they
use and the benefits they deliver to the user.
The interest in
chemistry-free CTP at last year’s Drupa was not just about
extra simplicity and convenience - it was also in large part
due to an increased environmental awareness in the printing
industry. Printers with green ISO credentials and
environmentally-friendly practices advertise the fact as
part of their selling process, with many reporting that the
emphasis on sustainable and eco-friendly practices actually
gains them new business.
But with
different technologies available from the suppliers, the
difficult question of which is best for you remains. The
technologies fall into three broad categories, based on how
the non-image areas are removed.
Direct on press (DOP)
These plates are imaged in a platesetter and put on press.
During the press start-up the non-image area is removed and
carried away by the paper during make-ready. The principle
is total elimination of all plate chemistry and this
approach is favoured by Kodak with its ThermalDirect plates
and Fujifilm with Brillia Pro-T. Both these plates rely on a
thermal platesetter to image them. Fuji’s Pro-T has an
impressive sensitivity of about 120mJ/sq/cm, meaning high
levels of productivity.
 The
high magnification image of Agfa's Azura coating shows
melted (fused) coating particles on the left and unfused
particles
on the right. This physically altered coating structure
eliminates the need for chemical development.
Critics of this
approach argue that the press isn’t designed to remove plate
coating. Converts to the technology would argue that it is
working just fine for them. With the annual worldwide offset
plate market in the region of 600 million square metres this
technology has the potential to completely eliminate the
tens of millions of litres of developer and processor waste.
Gum/water washed plates
Agfa and Presstek use thermal platesetters to write the
image on their plates. Agfa uses a gumming station to remove
the non-image area whilst simultaneously gumming the plate,
which is called Azura TS. This plate has a speed of about
210mJ/sq/cm. Presstek, with its Aurora Pro, has a similar
concept to Agfa but uses water rather than a plate gum on a
plate that has a faster sensitivity of 140mJ/sq/cm. Presstek
has high expectations of Aurora Pro, which it says combines
speed and robustness.
Critics of this
technology point out that this approach is not as
straightforward as the Fuji/Kodak route. The system still
uses water or gum in small amounts and it needs a small wash
unit. But supporters argue that the high pH developer is
completely eliminated and the additional wash step makes for
a simple and robust system. Agfa backs up its assertions by
claiming over 2000 worldwide installations of its
technology. However Fuji is gaining ground quickly and
claims 300 installations of the Pro-T plate in the UK market
alone. Kodak has a steadily growing following too.
Whilst perhaps
not as elegant and direct as the DOP approach, it is clear
that the ‘gum’ technology has been given a clear vote of
confidence by the industry. Agfa’s experience has shown that
a gumming / wash unit needn’t be an obstacle to popular
appeal so long as the plate performance is good.
Novel Technologies
Using inkjet to squirt an image on a substrate is an idea
that has been looked at a few times but so far without much
success. Technical concerns have centred on the speed of
imaging and the accidental splatter of ink onto non-image
areas. Israeli company VIM Technologies has adopted this
approach, adding its own technology to improve quality.
Whilst the systems may never be able to compete at the
higher end of the quality market, the ability to use a
standard inkjet printer to image plates will have a great
deal of appeal.
 Kodak's
Thermal Direct relies on the fount solution to moisten the
non-imaged coating, so that the tackiness of the ink pulls
the coating off on the first few press sheets.
After the
aluminium substrate has been sprayed with an image, a baking
step (which will use energy) hardens the ink into a tough
coating. Can VIM succeed where the others have failed with
inkjet CTP?
It will be interesting to see how it fares in 2009 as this
could be the lowest cost approach of them all.
Chemistry-free for all
These new plate technologies will not suit everyone, run
length limitations mean that the longer run printers need to
consider alternatives. There are ‘reduced chemistry’ plates
available from the major suppliers that use chemical or
physical image development and do need a traditional
processor along with process chemistry. However the plates
do offer the possibility of much longer run lengths if the
use of chemistry can be tolerated.
Computer to conventional plate
The concept of using traditional analogue plate for laser
exposure is still alive, however this isn’t a mainstream
approach and is unlikely to become so without a significant
technology breakthrough. Remember that this approach is
likely to still use a traditional developer and so may never
compete with the newer technologies on environmental
grounds.
China
China has seen massive investment in plate manufacturing
capacity and the first digital plates developed in China are
already in production. So far there is no independently made
plate that is competing internationally with the best of the
high-end products from the major suppliers. But it could
just be a matter of time before that changes, and when it
does there will be more price pressure on the plate
suppliers.
Violet chemistry-free
Thermal is not the only route into chemistry-free, but so
far it is the most popular route. However, Agfa with its N92
VCF Violet chemistry-free plate and Fuji with its Pro-V
plate offer a technology that may be interesting to owners
of violet platesetters wanting to go chemistry-free. Both
the Agfa and Fuji plate technologies are exposed with violet
laser energy to create image areas. The plate leaves the
platesetter and goes to a gumming unit where a small
pre-heat section amplifies the image. Then the non-image
area is washed away while the plate is being gummed.
Since the violet
chemistry-free plates could be fogged in white light,
on-press development is not a realistic option. Again,
purists might argue that this technology is not entirely
chemistry-free since it uses a gum. But the high pH
developer is eliminated, and with it many of the processing
variables. So owners of violet platesetters have good
technology options to eliminate chemical development as
well.
To gum or not to gum
That is the question. There is no denying the simple logic
that the Fuji / Kodak approach of removing the non-image
area on-press has great appeal. There is neither gum to
dispose of nor a gumming unit to run. Improvements to DOP
plate technology means that the plates are quick to reach
makeready point on the press and have proven reliable in
use. Although Agfa can’t deny the fact that its system does
produce waste gum, it argues that it is the gumming
principle that has actually delivered the working robustness
that has seen the Azura technology become the early leader
in terms of commercial success so far. But Kodak and Fuji
have high expectations for their products in 2009. Presstek
will be keen to assert its presence with Aurora Pro, noting
Agfa’s experience that a wash/gum unit is acceptable to the
market.
System costings
Opponents of the Agfa / Presstek ‘wash off’ technology might
argue that the wash unit makes the technology inherently
more expensive than the Fuji / Kodak approach. Certainly the
elegance and simplicity of the Fuji / Kodak approach is
highly attractive and hard to beat. However, all the
suppliers are keen to do well in this new market and are
backing it to grow dramatically from a few thousand
customers today into a mainstream technology in the future.
The suppliers will all position these new technologies as
premium priced, but nonetheless they will all be keen to
quote competitive pricing depending on the plate volumes and
plate gauges required.
Eco-friendly printers
As society increasingly looks to eco-sensitive approaches,
printers that publicise their commitment to using recycled /
recyclable materials and chemistry-free CTP are attracting
new business.
The printing industry faces turbulent times and many are
preparing for reduced profit margins and lower revenues.
Surely the business benefits of implementing environmentally
friendly technology have to be worth considering for any
printer?
Fujifilm's Brillia Pro-T is a highly
sensitive develop on press plate.
 ISO
14001 was published recently and rather than being a
prescriptive list of ‘must do’s’ it focuses instead on
establishing and continually improving an environmental
management system. Going green is one thing, getting the ISO
accreditation and using the green credentials to your
business benefit may be just as important.
Which is the best plate for you?
The new technologies remove high pH developers from CTP,
removing variables and improving system consistency. In
themselves these are important benefits, but coupled with
the green arguments these new CTP technologies become very
attractive. But there are subtle performance differences
between the different plates that will need to be assessed
before you make your decision to change to one of them. Run
lengths on the different products depend on individual print
conditions, the ink, press, paper and so on. No two printers
are the same, making it hard for suppliers to exactly define
parameters such as run length.
Productivity, or
plates-per-hour, will depend on the laser energy of your
platesetter, your resolution requirements and the
sensitivity of the plate that you plan to test. Determining
the best product for your individual business is best done
by arranging test plates, which the suppliers should be
pleased to arrange for you. Sometimes longer run lengths can
be squeezed from a given plate by increasing exposure
energy, but remember that will affect your platesetter
productivity. Different plates have different top-end
reproduction characteristics; these differences may not be
important to everyone, but be sure to make print tests if
really high quality print is essential to you.
Any printer that
is ready to upgrade from traditional CTP to one of the newer
technologies has an interesting choice to make and some
important benefits to gain. As always, the best advice is to
visit printers that have successfully installed the newer
CTP technologies, see how they implemented the technology
and whether they were able to use the technology to their
benefit. Compare the different suppliers against each other
and run several sets of test plates before making your
decision. Environmental considerations have never played
such a large part in the decision making process for CTP,
which is a tribute to the industry we work in.
This article is part of the Verdigris
series of stories about understanding the environmental
impact of print. The Verdigris project is supported by Agfa
Graphics, Canon Europe, Digital Dots, Drupa, Fujifilm, HP,
Kodak, Ricoh, Screen and Unity Publishing.
Philippine
Printing - Online is a member of the Verdigris Publishing
Network.
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