The term 'waterbased ink printing' seems to many screen printers to be a term akin to voodoo or dark magic. You have heard of it, you believe that maybe some people can do it, but the topic seems so mysterious to you that it might as well be a myth. Indeed, waterbased screen printing differs from standard plastisol inks printing in a number of ways, both beneficial and perhaps more detailed and intricate.
Matsui Color has garnered a reputation in the industry for being a leader in waterbased printing products, and recently they have introduced a brand new line of waterbased inks that take the guesswork and mystery out of the equation and give you a simple, effective, and efficient way to print waterbased inks easily and affordably.
The Matsui RFU series of screen printing ink is truly as the name implies - Ready For Use. The series includes 14 standard colors which are press ready right out of the container. But this isn't the true strength of the system. That strength is the ability to mix nearly any color in the Pantone spectrum using only these colors. A regular stock of only these 14 inks will yield any color you or your customer may need with only simple measuring and mixing.
Matsui provides a comprehensive yet simple guide for PMS ink mixing. Simply use your existing Pantone book as a reference and get the mix ratios provided by Matsui. Measure out the amounts of each ink needed and simply mix by hand (or mechanically for larger mix sizes). As the inks are waterbased they are very easy to mix quickly by hand using nothing more than a simple stir stick. You can easily mix only the amount needed for a specific job, or you can mix for stock as the ink can easily be stored once mixed for future use.
There are some special considerations when using waterbased inks, such as using an emulsion that is formulated to hold up to waterbased products (such emulsions are typically photopolymer emulsions, but there are also some dual cure emulsions that hold up quite well also). Also, it is recommended that you post expose your screens once washout is complete. This can help to even further 'set' the emulsion onto the screen and further prevent emulsion breakup, especially during longer run print jobs.
When printing, it is recommended to keep your screen flooded with the ink between prints. This will help prevent screen blockage from drying ink. As the ink is waterbased, you can usually spray a water mist onto the screen lightly to further help prevent drying. Matsui even makes some optional additives - a softening agent (which helps prevent mesh clogging), a fixing agent (which further helps bind the ink to your substrate), and a retardar (this extends the time it takes for the water to evaporate, extending your on-screen time for the ink). These additives are purely optional and intended to assist you, and not necessary for printing. You can even get these additives pre-mixed in the proper ratios - all additives together in one container for extremely easy use. You will also need an accurate scale if you intend to create your own ink colors from the 14 provided.
Finally there is a product called Trans-White. Although the name would imply a white ink (which it is), it is not intended as a standalone ink. Rather, it is used only as a mixing ink base for certain color formulations. This ink is necessary if you want to gain the full benefit of the RFU series as mixing inks, but won't be needed if you use the inks as standalone.
Texsource offers all colors in the RFU series individually, but we invite you to take full advantage of the flexibility of this line and get the full Matsui RFU ink kit (found on our website at www.ScreenPrintingSupply.com). Here you can buy a base kit, or expand by including a proper emulsion, scale, or color chart.
Want to see the Matsui RFU inks ink action? Have a look at this quick video using inks in the series to create the colors needed for this shirt design. In addition, you can easily see preparations considering emulsion, post exposure, and just how easy proper measurement and mixing can be.
Here, Ryan at Texsource performs a quick 3-color print job for a 4th of July shirt using only Matsui RFU inks.