There are so many options for screen printing ink, It can be hard finding the right one for you, but that does not have to be the case.
There are 2 main types of inks used for screen printing. Plastisol Inks and Water Based Inks. Plastisol Inks are used mainly on garments compared to water-based inks, which can be used on more materials such as paper, wood, cardboard, and garments.
Both behave differently, and there are derivatives of each type as well. If you are looking for the best ink that fits your needs, keep reading.
Plastisol Inks For Screen Printing
Plastisol Inks are made out of plastic PVC (polyvinyl chloride) non-phthalate. Many screen printers begin their screen printing journey by using it because it has an easier learning curve due to its 100% solid base. This is its strong point because it produces bright and opaque results. Plastisol inks only cure at high temperatures (320°F), which makes it impossible to dry when unattended without a lid cover or sitting on a screen for days.
Curing and flashing plastisol ink can be done using a heat gun, heat press, flash unit, or a conveyor dryer. Each method will require a different time to cure based on the specified units. To find out if the plastisol has been appropriately cured, perform a stretch test. Grab your garment and stretch the cured ink. You’ll know it has been well made if the ink does not begin to crack.
Since plastisol ink is high in viscosity, you may color match a specific Pantone color by mixing the correct ink. Use a Pantone Mixing system and Hex converter to color calibrate the desired color match correctly.
Plastisol ink is thick and lays above the garments as an added layer after a pass has been deposited. Darker garments will need multiple passes to create a vivid image, while lighter garments require fewer ink deposits.
Low/Rapid Cure Inks
Low cure and rapid cure inks are thinner versions of plastisol inks. They require a lower temperature to properly cure at (260°F-275°F). These inks are also much easier to work with as they have a buttery-creamy texture compared to regular plastisol inks. Note that these inks have a slightly lower opacity because of their lighter volume. To achieve a brighter image, use a white under base or deposit multiple passes if necessary.
Specialty inks are plastisol inks with an additive mixed into them in a 2-in-1 system. They are commonly premade ready to use out of the box with no mixing required on your end. However, you can create your own specialty inks if you’ve got the materials to do so.
Metallic Gold Ink
Metallic flakes mixed with gold plastisol ink
Metallic Silver Ink
Metallic flakes mixed with silver plastisol ink
Glow In The Dark Ink
Phosphors capture light and create a glow effect in a dark environment. It is recommended to mix with a white or fluorescent ink base for a stronger effect.
Plastisol additives generally come in as a base, unlike specialty inks. These do require mixing on your end. Please read the instructions on the container as they do require specific ink-to-additive ratios.
Creates a print to puff up and form a 3D effect
Reduces the thickness of plastisol ink and lowers cure temperature
Increases the thickness of plastisol ink, primarily for thinner low cure inks
It adds extra elastic properties to the ink for a longer life span
Water Based Ink For Screen Printing
Water based ink consists of dye or pigment with water as the solvent mixed in together. This makes water based ink considered eco-friendly as it produces less waste overall. Water base ink does take a toll on opacity due to its high percentage of H2O. Overall this kind of ink completely soaks into the fabrics which gives them a soft feel. Traditionally it is considered Ready For Use (RFU).
The recommended time to properly cure water based inks is at (320°F) for 2-3 minutes. Always check the inks manufacturer’s recommendations first as they all may vary. Unlike plastisol ink, water based ink cures the best by using a forced air dryer to let the water evaporate evenly. You can still get by with a heat gun, flash unit, and a heat press as an alternative.
Make the habit of flooding the screen with ink right after a pass to prevent the screen from clogging up. Remember, water dries, and water based inks contain more water than pigment or dye. Always close the lids from the container to prevent any ink from drying. If a screen so happens to get clogged, simply spray some water over the mesh to reactive the ink.
It’s important to have a compatible photo emulsion to pair up with water-based inks. Some inks can erode photo emulsion after a few minutes of screen printing. Consider adding an emulsion hardener to your washed-out screen after exposing an image if your emulsion has that effect. This can remove the learning curve of a new photo emulsion brand if you don’t want to switch.
High Solid Acrylic Ink (HSA)
HSA ink is a new formulation of its predecessor RFU. It combats the main issues that are present with traditional water based inks. It acts very similarly to plastisol. HSA inks can stretch as it is thicker, offers higher opacity, and it does not dry as easily. It is still considered eco-friendly.
The softest prints are made possible with discharge inks. Discharge ink is a form of water based ink that essentially bleaches garments back to their original color. It soaks into the fabric itself, leaving no dye behind. Because of this, it is geared towards darker cotton garments. Mixing discharge ink and color pigment does provide a unique effect as it thoroughly bleaches and dyes the fibers with a soft feel.
Discharge inks function with the help of an active agent that allows them to work correctly. Mix the discharge agent into the final ink mix at about 5% of the final weight to fully activate the discharge ink. Use a kitchen scale to compound your ink accurately.
Curing discharge inks require more energy. Water needs to evaporate out of the garment before actually curing. Discharge inks cure at (320°F). Using a forced air conveyor dryer or a forced air flash unit is optimal, although an infrared flash unit and conveyor dryer will work with a longer cure time.
If you’re going for a soft and eco-friendly route, consider choosing water-based ink.
Plastisol inks are a great choice for bright and opaque finishes that last a long time.
If you’re contemplating between both, consider sampling a pint size of each ink.