CR Blog

Burning Issue

• Posted by Patrick, 1 November 2007, 19:26
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In a desperate attempt to impress our readers, we decided to set fire to the cover of the new issue of CR.

Yes, OK, we know laser-cutting’s not exactly new - we did it ourselves for our October 04 cover - but this one is all a bit more complicated. The November issue has a theme - Work in Progress - so we knew we wanted to do some kind of special cover. As luck would have it, Richard Dyson of Trilogy Lasercraft, who did the previous cover, came down to see us and offered his services once more. It seemed to us that the technology offered some relevance to our theme so we gratefully accepted.

Laser-cutting has been around since the early 90s. A Californian company – Lasercraft Inc – built 14 machines, only two of which are in the uk, one being at the Cambridgeshire site of Trilogy Lasercraft. The system works by scanning a partly-focused laser beam across a thin copper ‘template’ that has been etched through with the image to be cut in the paper. The scanning beam carrying this information is then refocused onto the paper where it vapourises the required material which is drawn off as smoke, above and below the sheet, by the exhaust system. The machine can handle sheets of paper from a4 up to 700mm square (90 to 350gsm is best) but the total size of the area to be cut away cannot be wider than 140mm. Although the process is more expensive than die-cutting, it creates far more complex results.

We asked illustrator Kam Tang to create our cover image. We explained the theme to Kam and put him in touch with Richard so that he could take into account the peculiarities of the process. Kam, as we had hoped, came back with a fabulously intricate idea based on a piece of carbon turning into a diamond. Once we’d agreed the artwork with Kam, we had the covers printed. A copy of the part of the artwork to be cut was then sent to Lasercraft Trilogy as an eps file. They were able to run some sample copies on small flat-bed lasers to highlight any registration issues and, crucially, to identify any weak spots in the design that might not stand up to the binding process or to heavy handling on the news-stand.

Once we got the proof back, our art director, Paul Pensom, Kam and Richard all worked together to amend the artwork to strengthen it. Further samples were then sent out to our printer, St Ives, to run a binding test. This threw up some other weak areas, but once those were strengthened we were ready to go.

Lasercraft then created a template or stencil which is photo-etched in thin copper sheet. In production, our covers, supplied as trimmed sheets with bleed, were run by belts down to the machine and positioned precisely below the template. The high powered laser beam (3.5Kwatts of infra-red power) was scanned across the template and, where the image had been etched through the copper, the beam passed though and vapourised the paper beneath it.

We then repeated this 23,000 times at a rate of about 450 sheets an hour. Et voila.

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