Plastisol, Waterbase, Discharge…Oh My! The 3 main screen printing ink types and what you need to know My number one tip for creating garment graphics is to start with the end product in mind and work backwards from there. Having said that, before actually diving into designing the graphic you need to commit to understanding the different screen printing ink types available to you, as it will then allow you to achieve the design style you have envisaged without wasting valuable time. A classic example of knowing your craft (and something that actually happened to us), was one design that had a very fine, distress texture throughout it. We wanted the print to feel soft to touch, so we specked the artwork to use water base ink. When printed, the delicate details dried up in the screen, rendering them basically invisible, it appeared to be a flat color design with only the roughest sections of the texture shown. A better solution would have been to make the texture twice as thick, so that even if the finer details dried up a little it wouldn’t completely disappear or become one large ambiguous splotch. In this master class we will take a look at the different types of ink for screen printing. There are three main types of screen printing ink that all inks are derived from. So it won’t take long to learn the key points and knock your next t-shirt design out of the park! What is Screen Printing Ink? Even in today’s digital print world, screen printing is still a very viable method of transferring a design to a substrate (object). You can screen print anything from paper to wood to metal and of course, to fabric. The one thing that allows us to print on so many different substrates is the ink. For textile printing the three main types are: Plastisol, Waterbase and Discharge inks. Some people would argue there are only two types of screen printing inks, Plastisol and Waterbased, so why have we added Discharge as a third ink type? You’ll have to read on for the answer… Plastisol Plastisol is a PVC resin based ink, that can be pigmented. Plastisol inks are the standard ink type used in textile printing. Plastisol inks are not affected by the environment, meaning the ink will not cure or dry just by leaving it out in the open air. The ink needs to be heated to a certain temperature to fully ‘cure’ (set and bonded to the fabric or substrate). From a base plastisol ink, many specialty inks are derived: Metallic inks, Fluoro, High Density, Puff, Glitter, Glow in the Dark, Suede, Clear and more. Advantages of Plastisol: High Detail. The benefit of Plastisol inks is it’s ability to print fine detail. Making it perfect for graphic designs with line points of 1pt or for distressed ageing textures applied to the design. Vibrant Colors. Plastisol Inks provide the best color reproduction on both light and dark garments and tends to be the most hard wearing, (also holding its color over the longest period of time). User friendly. Plastisol inks are a screen printers best friend, Plastisol inks do not “dry” in the open air so they can be left in the screen or bucket overnight without drying up. Largest range of colors. Any reputable screen printing facility should be able to color match any Pantone color specified for a design, if they can not provide this service they will at least have a large amount of pre mixed colors from the ink manufacturer to work with. Disadvantages of Plastisol: Plastic-like hand feel. The main downside to Plastisol (and it is a big one) is it’s hard, non breathable, plastic-like print feel (which accounts for its longevity). This sticky plastic hand feel is a major turn off to some buyers because of the way it feels, so it’s very important to keep this in mind. Prints can not be ironed. It’s important to keep Plastisol away from heat and heated objects as it is a thermoplastic (becomes soft when heated and hard when cooled) and will remelt if it comes in contact with them, it’s for this reason, that plastisol prints cannot be ironed. If an iron touches a print, it will smear the ink (and wreck your iron!). High curing temperatures: Plastisol ink needs to be ‘cured’ (melted and bonded). The ink is exposed to heat so the molecules of PVC resin and plasticizer melt and then solidify. Plastisol cures at temperatures from 149 °C to 166 °C (300 °F to 330 °F). These high temperatures can burn lightweight fabrics. Check with your screen printer if you plan to print on garments that use a high percentage of synthetic material. If a soft hand print feel is what you are looking for, don’t give up on Plastisol inks just yet… enter the soft hand Plastisol! SOFT HAND PLASTISOL Soft Hand Plastisol ink is Plastisols’ sweeter sibling. It can be colored (or pigmented) and unlike it’s heavier plastisol twin, is designed to produce a print quality similar to water base inks (inks which are absorbed by the fabric), but does not lock garment fibers down and the print will appear “lighter” after washing. Why not just use soft hand plastisol all the time? Soft hand Plastisol is produced by mixing a reducer base into the Plastisol ink. Think of the reducer as a ‘diluter’, it’s like adding extra water to your favourite cold beverage, it’s still ink but not as concentrated, therefore the colors desaturate. For example, whites become slightly off-white. If you’re printing on white or light base color garments then you should have no problems, but soft hand plastisol doesn’t fare so well on dark garment bases due to the high opacity. On dark garments expect for the colors to desaturate, this can work in your favor if you are going after a vintage t-shirt design look where the print colors don’t have to be vivid or 100% accurate. Like standard plastisol, it can print very fine line counts and detail and it has a great color spectrum to select from. Environmental Considerations If like us, you are concerned about the environmental impact of producing your products, then it’s worth considering how your print factory handles the cleaning of it’s screens and printing equipment when using Plastisol inks. In order to remove the ink from the screens, squeegees, spatulas, flood bars and work surfaces, it is necessary to use some type of solvent. Mineral turpentine being one of the most common. The waste ink and the solvent must be disposed of properly in order to minimize environmental impact and not just flushed down the drain. Fortunately, environmentally-friendly solvents are available today, but it’s important to find out if your print suppliers are using them. To add to this, there are many types of filtration and cleaning systems available, that capture inks and solvent residues before they enter the sewer systems. ART REQUIREMENTS: Halftone: 20 lpi Line Weight: 1pt minimum Max Art Size: Check with print shop what the maximum art size is as this changes from factory to factory. In general, an A3 page size would equate to a large chest print for a men’s garment. Image Resolution: 300 dots (pixels) per inch at the actual size of the design to be printed. Image File Types: Most print shops will accept .psd, .tif, .jpg, .gif and .png. Vector Art File Types: Vector PDF, EPS, AI or CDR Files. RECOMMENDED GARMENT/FABRIC: Weight: 2.25 oz min – 10 oz max We recommend using 100% cotton garments or 50/50 cotton/poly blends. Plastisol Ink Garment Care Instructions When caring for garments printed with plastisol inks we recommend the below wash instructions: Turn the shirt inside-out. Use a delicate wash cycle with cold water and a mild detergent. Tumble dry on low. Do not dry clean. Do not bleach. NEVER iron on print. Water Based Ink Water based ink is a popular and attractive looking ink chosen for it’s ultra-soft feel and general usefulness. It is a versatile ink and can be used on garments and finished products (ie: manchester, tote bags) but is also the main choice for yard goods (ie: fabrics). Water based inks have a ‘soft hand’ feel, (where the print/ink cannot be felt easily by hand), this is because the ink is absorbed by the fabric. Using Water based inks generally consists of a two part system mix of a base or solvent (water) and pigments (colours). Water based inks cure through the process of evaporation. During the curing process a portion of ink remains to color the fabric. Whereas Plastisol inks create a film and sit on top of the fabric, water based inks penetrate into the fibres of the fabric to lock in the color. Water based inks dry rapidly in the open air, for this reason a courser (less tightly weaved) silk screen mesh is used to print the ink through. A lower screen mesh count means there will be a loss in fine detail quality. A side note on mesh counts: To understand screen mesh counts and how it affects image quality, imagine trying to print a t-shirt design using the mesh of a fly screen door. Fly screen mesh is made of metal threads that criss-crossed to create the mesh. Looking closely at the mesh you will see it is now made up of tiny little squares, these squares are what lets the air pass through but keeps the flies and other insects out. The squares of the mesh can be thought of like single pixels, the finer the mesh the smaller the pixel, the finer the mesh the more pixels can be crammed into the same space. So, for silk screen mesh used in screen printing, the tighter the weave the more detail can be achieved as long as the ink is fine enough to pass through the mesh. Advantages Of Water Based Ink Great “soft hand” feel: Water based inks are soft to the touch when running your hand over the print. This is the biggest advantage for water based inks. Good color selection: Water based inks are available in a great range of colors. Prints well over seams, stitching and pockets: Since waterbased inks absorb into the fabric, the ink is applied over seams much more evenly as opposed to Plastisol inks that will build up uneven surfaces and “blob”. Disadvantages Of Water Based Ink Dries in the open air: Screen printers must work quickly and make sure the area on the screen to be printed is flooded (fully covered with ink) any time the screen is off the fabric to be printed or the ink will dry in the screen. Lower detail quality: To prevent ink drying in the screen, lower mesh count silk screen are used to print the waterbased inks. Lower mesh count equals less fine details can be achieved. Muted colors on dark fabric: Because the ink is absorbed into the fabric the ink will take on some of the garment color, this tends to mute the printed color on dark fabric. Halftones and Gradients: Prints that have halftones and gradients are harder to print because coarser mesh screens used for water based inks struggle to hold fine halftone dots. More Expensive than Plastisol: Printing with water based ink is more labor intensive because of the speed, tools, supplies and extra experience that is required. For these reasons factories tend to charge more. Waterbase Ink Garment Care Instructions When caring for garments printed with water based inks we recommend the below wash instructions: Turn the shirt inside-out. Use a delicate wash cycle with cold water and a mild detergent. Tumble dry on low. Do not dry clean. Do not bleach. Do not iron on print. Discharge Ink Now it’s time for our third ink type, Discharge! As we said at the beginning of this article, some people would argue that there are only two types of ink, Plastisol or Water based inks, and they would be right. However, the dyeing method used by discharge inks is so different to water based inks that we feel it deserves a mention! How does discharge ink work? Discharge inks are part of the water based family but what sets them apart is the way in which the dye is applied to the garment. Discharge inks use a chemical called Perolite to remove the dye from the garment exposing the raw fabric. Contained within the discharge ink is the color pigment of choice. When the print area is heated the Perolite bleaches the fabric leaving the pigment behind to color the threads of the garment. Since the pigment is dyeing the actual fabric threads (and not just sitting on top of the fabric threads) the printed area remains as soft as the fabric itself. If you’ve ever been in the room with someone printing with Discharge inks, you will immediately notice the pungent smell. The first time I experienced the smell it made me quite nauseated, but you get used to it after a while. Discharge inks contain traces of formaldehyde (and other not so pleasant chemicals) which are released into the air when the ink evaporates during the drying process. Graphic Design Considerations Unlike Plastisol inks, discharge inks dry up in the screen very quickly. Courser silk screen mesh is used to prevent the ink drying and this coarser mesh means fine details are a no go. ART REQUIREMENTS: Halftone: 30 lpi Line Weight: 2pt min APPLICABLE GARMENTS: Weight: 2.25 oz min – 8 oz max We recommend using 100% cotton garments only Warning! Cotton/Poly blends yield unpredictable results as the polyester threads can not be discharged therefore, only the percentage of cotton in the garment will be discharged properly. Discharge Ink Garment Care Instructions When caring for garments printed with discharge inks we recommend the below wash instructions: Turn the shirt inside-out. Use a delicate wash cycle with cold water and a mild detergent. Tumble dry on low. Do not dry clean. Do not bleach. Do not iron on print. QUALITY CONCERNS: Due to the nature of discharge, color matches are problematic. We cannot guarantee exact PMS matches. Due to the variance that is possible in the dye process and the fact that discharge inks react differently on different color grounds, we cannot ensure that the color will match on every garment. Previous article Screen Printing Metallic Inks: The Definitive Designers Guide. Next article Screen Printing Puff Ink – The definitive designers guide.
