A Day in the Life of ....A Colour Technician

Tradeprint built its early reputation on an almost fanatical drive for colour and print perfection. And that obsession is still a hallmark of Tradeprint today and, especially, those in our pre-press department.

Every day we receive hundreds of orders, and every day we process millions of bytes of data, analysing PDFs from morning to night to ensure that everything is exactly right. Over the years, we’ve developed a plethora of cutting edge automation and quality control techniques that help us deliver astonishing efficiencies without ever compromising on our quest for the best quality achievable.

Not everything can be automated, however, and that’s where our experienced pre-press team come into their own. Take Greg Smith, for example.

Greg Smith, Colour Technician marvel.

Greg Smith, technically a colour marvel.

Greg is our Acting Pre-Press Supervisor and an expert in colour management. Greg joined Tradeprint 2 years ago as a Pre-Press Operator and gained invaluable experience at the coal face.”I’ve dealt with tens of thousands of orders over the years,” says Greg, “and from experience I appreciate the importance of processes to ensure the stability of colour output across the vast number of printing devices we operate at Tradeprint.”

Our processes are designed simply to foster an internal attitude of excellence in colour management.

The Process

Throughout the month our fleet of Litho presses need to be monitored to ensure they always comply to ISO12647-2 colour standards. It is critical that the machinery is monitored regularly, and each month Greg adheres to a strict timetable of calibration across the presses and supporting devices.

Calibrated devices ensure consistency with our final prints, allowing customers to trust the CMYK file they send will print to the colour they request.

A test file is printed on the press that contains colour references that show both solid colours and gradients in 10% increments from zero to one hundred percent. These are measured and compared against the ISO12647-2 colour standards. The solids are measured and densities altered at the press to produce colours with l*a*b values within the expected tolerance range.

The gradients are measured by the dot gain of the ink at each incremental value. The pre-press workflow allows us to correct for natural gain of the ink.

What is Dot Gain?

dot gain

We monitor dot gain so closely, because it potentially has a massive impact on the ‘density’ and ‘tone’ of a printed job. Throughout the printing process, the halftone dots used to build up the printed image can be squashed and distorted fractionally throughout the many stages. The ink used, the printing blankets, the fountain solution and the unit pressures can all have an impact.

If the measured dot gain is not within an acceptable range, the colour correction curves are altered in the pre-press workflow and the files printed again until the dot gain falls within the expected range.

This is done across the fleet of presses and all presses are calibrated to the same spec to ensure colour matching regardless of which press is used.

The plate setters are also calibrated to compensate for the natural bias in the plate-makers. This is done by printing plates with a set of test gradients with a dot gain of zero to one hundred percent in ten percent increments similar to measuring the ink dot gain on the press.

These actual values are then used to create a calibrated set of values that take the natural spread into account so a 5% dot in the artwork file will give a true result of 5% on the printed plate. These two processes ensure that ISO quality standards for colour management are achieved on every print.

We carry out this process every month, without fail. The calibration process is triggered by the number of sheets printed or the time passed, and is never missed. This is just one of the quality management processes at Tradeprint, and one of the factors that contributed to us winning the coveted Printer of the Year Award in 2014.