High Density printing:
 is the process of printing a specially formulated ink through a very thick stencil to achieve a raised, glossy smooth print with very sharp edges. Unlike Puff inks, which have a flat, rounded and somewhat dull appearance, High Density prints result in bright, glossy distinct colors. The result is an appliqué effect similar the "welding" or radio wave embossing but at pennies per shirt as opposed to $2.00 plus for the welding method. High Density printing is done using basically standard textile screen printing procedures and equipment, with some variations.

Water-based Ink Systems:

Water-based inks are defined as those that utilize water as the main solvent. That does not mean, however that water is the only solvent. It is significant to note that many water base inks contain “co-solvents” which may even be petroleum based solvents. The reason these co-solvents are used varies, but one of the key reasons is to decrease the time and heat necessary to cure the ink film on the fabric.

Advantages of Water-based Inks:

Water-based inks are a good choice when a “soft hand” is desirable. A soft hand is the condition where the ink film cannot easily be felt with the hand when passed across the surface of the fabric. This affect is often used as an argument for why water-based is preferable to plastisol as plastisol has more of a hand than water-based.  Water-based ink also has the advantage of being an excellent ink system for high speed roll-to-roll yardage printing. Such printing is done on large sophisticated equipment that has very large drying (curing) capacity.  Water-based ink also is a good choice where ink penetration is desirable, such as in towel printing. Towels have a high nap fabric that must be printed in a manner where the ink penetrates or wicks through to the base fabric for adequate coverage. Water- based inks that are designed to wick into the fabric are excellent for this application. Ink wicking is not a desirable affect in most other fabric printing as it will destroy the design and registration of multiple colors.

Disadvantages of Water-based Ink:

Water-based ink is much more difficult to cure than plastisol. A shop that is interested in printing water-based ink must have the drying capacity to remove the water. The dryers used for water-based printing tend to be larger than those needed for plastisol. In plastisol printing, the ink film must only reach the cure temperature for a brief moment. With water-based ink, the temperature must be reached and then held until all of the solvent (water) is removed.  There are water-based ink that will air dry but they are usually only acceptable for craft level printing as the room required for curing greatly reduces productivity. Many water- based inks can also be more quickly cured with the addition of a catalyst that will assist the heat in the curing of the ink by continuing the cure even if all of the water is not removed in the dryer.  The disadvantage of a catalyst is that once it is added to a water-based ink, it creates a time limit or “pot life” where the ink must be all used in a certain time or be discarded. Most catalyzed water-based ink pot life’s are between four and twelve hours.

Since water-based inks contain water as an evaporative solvent, care must be taken to prevent the ink from drying in the screen. If water-based ink is left in open mesh for even a short period of time, it can clog the mesh and ruin the screen. Practiced water- based ink printers must always be conscious of how long a screen sits between prints to prevent the ink from “drying in”. While modern water-based inks are less prone to this phenomenon, it is still a concern.  In addition, when a water-based print job will take more than one day, the ink must be removed and the screen cleaned with to prevent drying. The ink is then put back in the screen on the next work day and the job is continued.

Water-based ink is also much more aggressive than plastisol towards the emulsion that is used to create the screen stencil. Emulsion manufacturers all make “water-resistant” emulsions that must be used for water-based printing. If standard emulsion is used, the water-based ink will destroy the stencil by melting the emulsion is as little as a few minutes. Even when the proper emulsion is used, screen life tends to be much less with water-based printing than it is for plastisol printing. 

Discharge Printing:

You may not be familiar with the process of discharge printing, so lets take a moment and let me explain and hopefully answer a few questions you may have.  Discharge printing is the process of re-dying the fabric with colors.  This is done on shirts that are dyed with reactive dye and will allow for the white fabric of the shirt to be recolored with the new applied color.  This allows discharge inks  on a dark fabric and after exposed to heat for several moments to produce colors.  As you can see here, very bright and vibrant.

It is said that a picture is worth a thousand words... this is a 12 color discharge print on multiple colored shirts.  The biggest reason to use discharge inks as apposed to an oil base product such as plastisol, is the breathability of the ink itself.  This reason alone gives the print a much softer hand and feel to the product.  Most printers will not be familiar with discharge printing and will limit you to 4 to 6 colors because they are not comfortable  with the process.  At SNR Graphics, we feel that it is important to provide a product that best matches the artwork.  We match Pantone colors by testing the shirt that will be used in production.  Since we mix each batch as needed, and have thousands of custom mixed colors, we can adjust our inks to correctly hit the pantone color on your product.  It is important to be able to do this each time fabric is brought into our shop so we can ensure that it matches what you ordered last time, or make the adjustments accordingly so it will.  Does your screen print shop do that?  

Plastisol Ink:

Plastisol inks are widely used in garment printing. They are easy to print, do not dry in the screen, can be very opaque on dark garments, and will adhere to most textiles. They are composed primarily of two ingredients, PVC resin (a white powder) and plasticizer (a thick, clear liquid). Plastisol inks have one outstanding characteristic, they must be heated to dry. They will not dry, or cure, at normal temperatures. For a complete cure, they must reach 290-330º F (143-166º C).

Plastisol inks can be printed on virtually any surface that can withstand the heat required to cure the ink and is porous enough to permit good ink penetration. Plastisol inks do not color the fibers like a dye. Instead the ink wraps around the fibers and makes a mechanical bond with the fabric. For this reason, they will not adhere to non-porous substrates such as plastic, metal, and glass. They also will not adhere well to woven, waterproofed nylon material without adding a bonding agent.

Health, Safety, and Environmental Concerns
Plastisol inks are innocuous when used with reasonable care. A true plastisol ink contains no air-polluting solvents or volatile organic compounds. The manufacture, transportation, storage, use, and disposal of plastisol inks do not cause injury, illness, or environmental contamination as long as the appropriate safety and environmental protection procedures are followed. Most plastisol inks have a Health Rating of 1 (hazard - slight), a Flammability Rating of 1 (hazard - slight), a Reactivity Rating of 0 (hazard - minimal) and a Personal Protection Rating of B (wear safety glasses and gloves).

We do use plastisol inks at SNR Graphics for some fabrics that will not allow us to use water based, or discharge products.  We also have a PVC free plastisol alternative that we try to recommend prior to printing plastisol.  As a customer if you are determined to use it.  We will do so.

Website Builder