Tony Palmer, production director at Essential Workwear, explains how to create a perfect high build print with sharp edges
In the endless search for that something different to show clients, we often attempt to showcase ‘tactile’ prints. These can include a myriad of special effects that ranges from expanding ink to ink that feels like suede or leather – there is even ink that looks and feels like it was printed 25 years ago and cured with a heat gun.
To achieve a raised effect we have a couple of options: we can add a chemical to the ink that when activated by heat will expand and puff up in the same way baking powder lifts a cake, or we can lay down an extra thick layer of sturdy high build ink. Expanding ink can be manipulated by altering the strength ratios to give either a matte appearance or a full-blown sponge effect; these are fantastic ways to achieve differing fashion looks, but the drawback is they leave a slightly rounded edge to the graphic because as the ink expands upwards, it also expands outwards. High build ink has no expanding qualities, however the high density of the ink enables it to retain a sharp edge after it has left the mesh.
Printing is the art (or witchcraft) of pushing ink through holes in a set pattern. If the hole we push the ink through is only 1mm deep, then we leave behind a 1mm thick deposit of ink. If we increase the depth of the hole to 3mm, we can leave behind a 3mm thick (tall) deposit of ink. The first step in the process is to make a screen with a deeper hole; we can do this either by using multiple coats of emulsion to build up a thick layer, or by using a sheet of capillary film, which is basically a sheet of unexposed emulsion manufactured to a specific and constant thickness. We used a 300 micron film in this step-by-step; if an even higher lift is needed, we can use two screens set at different off-contact distances. Design is important here as large, open areas of high-density (HD) ink can be uncomfortable to wear, so try and use the effect to pull out details or elements you want to highlight.
We began by creating two high build screens and two base screens – as we used white HD ink on a white base, this gave us a subtle raised look that complements the design. The screens were coated following the manufacturer’s guidelines.
As always in screen-printing, there are different methods to achieve the same result and finding the right one for you is a matter of trial and error. We like to use a thin layer of emulsion to adhere the capillary film to a fresh, clean, high-tension screen.
We imaged the screen on a Spyder II from Exile Technologies – supplied by MHM Direct GB and set up to work with MHM presses – to give us super opaque images; we needed to increase the exposure time to cure all the way through the thick emulsion and using the Spyder II meant there was no need for vacuum, which could have let light creep round the image. We used 300 micron Chromaline Phat film on a 43t mesh and exposed it for 200 light units using an LED light source.
Developing these thick stencils can be tricky, but the main thing to remember is that all of the emulsion is on the shirt side, this gives us our depth. Washing out from the ink side will just result in blowing off the image as it is only adhered to the mesh by the small layer of emulsion we used to stick the film on with. Gentle rinsing is the best method as we need to wash away the unexposed emulsion from the image one layer at a time rather than trying to power blast through the image and risk damaging the soft edges.
Time to print
We used a water-based white from Magna Colours – Aquaflex White V2 – as this gives a softer feel than traditional plastisol and it has a good, stable, open time in the mesh. The goal is to create a solid layer of white for our HD to sit on. This was printed on an MHM S-Type Xtreme 10/12 automatic press through a high tension 43t mesh using a 65 durometer, 65 shore sharp blade at 15° angle at low speed, double print. It was flashed for two seconds on pre-heated boards and then hit again using the same settings, this gave us a good opaque base. The key is not to push too much ink through the fabric, we want to sit our second coat on top of our first coat to give good visual strength.
The HD ink we used was Wilflex Sculpture base and normal white mixed at 50/50 ratio. It was applied to the flashed base using very low off-contact because we wanted to allow the ink to shear out of the deep emulsion hole we made in our high build screen. Using a triple blade durometer 65/90/65 squeegee reduced the bend over in the blade as we were using very thick inks. A second screen was used to apply a further coat using the same settings, but this time the off-contact was raised to ensure the second ink layer sat on top of the first layer. If we hadn’t used this progressive off-contact method, the first print would have sat perfectly in the hole of emulsion of our second screen and the height of the build would have been lost. The T-shirt was sent through our Tesoma Drylight dryer, set at 170°C for 1min 30sec.
Step-by-Step: High Build Print
(1) For the high build screen, use a good quality capillary film – we used 300 micron – and then dry thoroughly
(11) Finish by putting through a dryer at the manufacturer’s recommended settings; we used a Tesoma dryer at 170°C for 1min 30sec