by Douglas Grigar, Master Screen Printer

(A version of this article originally appeared in the March 2007 issue of PRINTWEAR.)

What can we say about screen mesh? Quite a bit actually. It is one of the aspects of screen printing that presents itself as such a mystery. But with a review of the basic information about mesh, it’s possible to get a better understanding about how this critical issue affects the final print. The most important question in this quest: How do we choose the best mesh features for our use? There is a long list of factors about mesh and its properties that all drastically affect its performance; this article can only give justice to a few of the most important aspects. But let us at least dig into these here.

Construction from a Historical Perspective

Starting with the mesh threads themselves, under a microscope, we can see the smooth-walled threads of the most common choice of mesh – monofilament polyester – and see how the rounded, slick thread walls can help us with cleaning and reclaiming. The smoother surface simply will not hold emulsion like a roughened surface will. Our use of low elongation (LE) monofilament polyester mesh has long progressed past into the introductory stage. The now-mature product takes far less effort and time to produce a tight tension screen that is stable within just a few print/reclaim/retension cycles. And, the advancement of mesh chemicals and construction that followed the development of retensionable frames has further improved the performance of mesh; a great benefit for all types of frames…not to mention the benefit to users that comes with the superior mesh products now available.

Counting Threads

The most common and at least partially understood choice in mesh is the count of threads in a row occupying an inch or “thread count.” While this thread count generally dictates detail and use, it is only one choice in an array that affects printing ink volume, available detail, and tension. The more threads that span an area, the more threads will be available to hold bits of emulsion that make up the stencil. This translates to more detail since more of the area taken by the threads themselves means less ink can pass onto the print. The reverse is that the fewer threads that span an inch, the more room for ink to pass, but fewer threads will provide less attachment points for detail in the stencil.

[Figure 1: While there once was an industry tendency toward un-dyed mesh simply because of its lower cost, this trait is – thankfully, due to dyed mesh’s superior performance characteristics – a thing of the past.]

Through Thick and Thin

Along with the thread count, the thickness of each thread woven into the mesh dictates the open area of the mesh where the ink will pass onto the substrate. There are several choices for each thread count based on the actual thickness of the threads themselves when considering mesh threads that are spaced in the same count per inch. It’s often the case that manufacturers will offer several choices of thread thickness for each thread count, whereas suppliers will most often only carry one choice of each mesh.

Thinner threads are capable of holding and helping print finer detail, but typically are not as strong, resistant to abuse, or capable of holding as much tension without breaking. The thicker the threads, the stronger the mesh…they are also more resilient to abuse and more capable of higher tensions. The drawback is that once threads become too thick, they restrict ink flow excessively, making the images hard to print, and with much less detail. Heavy, thick threads are notorious for difficult printing.

After a short stint in attempting super-high tensions, most printers choose a more reasonable, mid-range thickness of threads and tensions, compromising on strength and detail. This mid-range mesh is what is most often available from the regional suppliers.

[Figure 2: A basic consideration when matching mesh to art is in knowing that the lower mesh counts tend to print at a higher volume or thicker layer of ink. Additionally, the printer should understand that higher mesh counts reproduce better detail, while the lower can hold only basic detail.]

[Figure 3: Once upon a time, there were proponents of multi-filament mesh. Given its propensity to hang onto not only ink but emulsion (during reclaiming) as well, it has long since given way to monofilament for textile printing.]

[Figure 4: This illustration demonstrates the relative difference in thicker versus thinner threads in the same mesh count. The effect of less available detail from the smaller holes – produced by thicker threads – is evident when evaluating the artwork (red) in the background.]