We only include a few key pieces of printing equipment on the plant list on our website, but I’m not sure whether I should go into more detail about our software, pre-press or bindery. What should go on the list? Do customers actually look at them?

I used to think it wasn’t important, until I started asking buyers this very question. The sophisticated, experienced buyer not only wants to see your list, but relies on it when making sourcing decisions.

The experienced print buyer, particularly one with a background in print manufacturing, knows precisely what equipment would produce a job most efficiently. These professionals take a look at a list and know instantly whether or not a plant can handle a particular job.

Since buyers are becoming more educated on printing, proofing and finishing technology and digital workflows, it’s also important you list your pre-press capabilities. Go into detail on your proofing capabilities; elite customers have preferences on the types of proofs they prefer.

The same goes for finishing. What services do you offer, on what equipment?

Do you have digital capabilities? Then make some noise about your digital strengths. Mail and fulfilment services are the number one ancillary service our US printers have added, so if you also offer them, put them on your plant list.

Bottom line? Always have an easily accessible full plant list on your website. Knowing that the experienced buyer is savvy enough to translate what your presses can and cannot do, and that the new buyer might be totally confused, you will need to offer plain-English commentary to help the newer customers appreciate what’s possible.

Margie Dana, founder, Print Buyers International

I want to reduce dust in the press hall, while also complying with ATEX regulations on explosive atmospheres. What should I consider?

Health and safety, and conforming to international standard OHSAS 18001, is a fundamental issue. On top of that, there is external pressure from the HSE to adhere to the COSHH (control of substances hazardous to health) law, which governs the use of chemicals and hazardous substances, some of which can be present in the press hall, and, as you mentioned, ATEX regulations, which are based on two European directives, and force employers to classify into zones any areas where hazardous explosive atmospheres may occur.

COSHH states that the main method of removing dust should occur at source. Proper in-house cleaning can reduce, and even eliminate, the requirement for ATEX zoning. We’ve found the above reasons are all behind the trend for companies to adopt high-vac solutions as their primary method of targeting dust.

You might think large-scale ventilation is the best option for air cleaning, but there are many arguments to opt for on-tool extraction directly at the source of the problem. In print, this would be placed at the slitters or folder cylinders, and would use a high-pressure vacuum system with relatively small bore pipes, preferably bespoke to each individual customer so that it can easily integrate into a press. The waste can then be transported straight to a convenient location on or near the press. The balanced system pressure means that extraction from slitter hoods in particular can be significantly improved.

One benefit of a good high-vac system is that it can double as a tool for general cleaning, eliminating the need for mobile vacuums and sweeping, which creates an enormous amount of hazardous airborne dust in itself. Mobile units are appropriate in some situations, but can become the victims of poor maintenance as well as causing trip hazards or manual handling issues.

James Miller, general manager, Dustcontrol UK

My client has specified uncoated paper for the inner pages of a high-quality booklet run. In the past, I’ve found that colours printed on uncoated stock can look flat. How can I improve this?

There was a time when choosing an uncoated paper to print high-quality images could mean taking risks with the print quality. Dark shadow areas and flat uninspiring mid-tone images were often a disappointment. Good planning is the key and with current pre-press and press technology, uncoated paper can be specified with confidence.

When a halftone dot of ink hits the paper, its spread is relative to the absorbency of the substrate. Increased dot size, known as dot gain, will be much higher on an uncoated paper compared with a coated paper. It can also vary depending on the type of uncoated paper being used. As the dots grow in size, the screen tints darken and the darker areas may fill in completely. The result will look flat and dull particularly in the middle tone ranges because the size of the dot is at a maximum. The effects of this dot spread must be controlled in order to obtain the desirable quality in the final print.

At the pre-press stage, it is necessary to open up the separation and decrease the dot size. Instead of opening up the entire image, which can also create a flat result, the densities and detail within the image should be considered, as the critical areas will vary. To increase the visual contrast, keep the shadows strong (90-95%), the mid- and three-quarter tones open and the highlight areas bright (down to 0%).

It is possible to control dot gain through digital pre-press by adjusting the ‘curves’. These controls will be particular to a set of parameters, which will include the press, the images and the paper being used. A curve can be built by a testing process that measures dot gain over a series of tonal steps on a particular press using a particular paper. This built-in curve adjustment will result in cleaner and sharper highlights and more detailed shadow areas.

Lower conventional screen values (133-150lpi) are often used with uncoated papers. However, if the repro has been adjusted correctly, high screen rulings can be used (175-200lpi) and the use of Stochastic screening will give better detail retention as this screening technique produces dots that are the same size and there is no detail loss in the darker shadow areas.

To improve trapping and achieve better colour stability in the shadows, it is desirable not to print more than 240% ink coverage in any one area. The use of UCR and GCR should be employed at the repro stage. This will also reduce ink drying difficulties sometimes associated with printing on uncoated papers.

Another suggestion would be the addition of fluorescent ink to the magenta, cyan and yellow process colours. This will increase the perceived reflected light of the paper surface.

Ian Knott, group technical business support manager, Robert Horne