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The continuing need for screen-printing
Nov 02 2011 08:39:37 , 2077

Rumours that screen-printing is on the way out still fly thick and fast, but its demise is far from reality as its true worth as a technique continues to benefit a vast range of applications. Although the most common argument we hear for and against analogue and digital is concerned with run lengths and the viability of high versus low volumes in practical and cost terms, there are still many jobs where the screen process excels and which will ensure its future is secure for many years to come.

 

The natural comparisons in efficiency come in the set-up and makeready for screen-printing which, by its very modus operandi, is complicated and time consuming. Conversely, to prepare a job for digital production, the process is relatively quick and seamless. But, even with the fastest ink-jet machines of today, most find it hard to compete with a screen press running full-on to produce high volumes.

 

PSPs who have in daily use both screen and digital equipment benefit from being able to make the choice between one and the other according to job type, end material and, to a certain extent, the behaviour of colour and ink on the final substrate. In graphics printing we hear endless stories about the analogue to digital transition and, while this is true and well suited to many applications, there is still a market for screen-printed output. Mentioned infrequently, too, is the fact that there is nothing to stop a job using both the screen process and ink-jet to create the best overall effect via a combination of techniques.

 

 

 

Comparisons of colour are often made between the two types of output and it's true that analogue production still has the flexibility for special and spot colours to be used, with most screen-printers having their own facilities to mix and match what's needed in house. With digital, meeting Pantone requirements, for example, relies on software algorithms and calculations to get the shade exact.

 

People often say that screen-printing's sheer depth of colour gives it a huge advantage, and this is because the process caters for relatively thick layers of ink which result in strong opacity and visual density. Digital printing tends to have a thinner ink deposit so its output can look less dramatic than its analogue counterpart.

 

But, although inks have improved and their coverage on different materials is now consistent and sufficiently opaque to be used for even the trickiest back-lit display, digital print still lacks in versatility of what it can produce. Where it scores on small and variable runs, plus the relative simplicity of set-up and run time, ink-jet continues to lag behind screen where specialist fluids are being used and where unusual finishes are required. All is not lost, however, and ink-jet deposition technology is being applied to many areas outside the graphic arts and industrial sectors as jetting principles adapt to address different markets. Likewise, we have seen refinements and modifications to engines which first allowed the use of white ink and, subsequently, have seen additions of clear varnish and metallic options.

 

Nonetheless, in areas where effects and functionality go one step further, screen-printing still excels and FESPA's excellent Sensations book provides myriad examples of output which simply cannot be produced digitally. With a screen press, as long as the right mesh and ink combination is used, there really isn't much restriction on what can be applied by squeegee. This is a very forgiving process and fluids, such as abrasive and perfumed inks and those that react to heat and light, are all perfectly happy with being applied via an analogue technique. So far we don't have print-heads or nozzles which are capable of producing commercial applications using many of the heavier viscosities and formulations that can be handled easily via screen-printing. This means that anyone wanting to specialise, for example, in scratch-and-sniff, heat activated, mirrored or non-slip products needs to stick with the screen process.

 

In more conventional graphic terms, digital has continued to score because of its flexibility and lack of chemicals; for its sheer convenience factor, it is difficult to challenge. In the early days of wide-format ink-jet, attempting to quantify the crossover point between digital and analogue resulted in fairly low numbers, with 25 being typical. Today it is testimony to the advances in machine build and technology that volumes of several hundred are viable for digital output but, for any non-standard ink or finish, and for optimum creativity, screen-printing is still a force to be reckoned with.