Step-by-Step Guide to DTG Pretreatment for Perfect Prints

To achieve optimal results with direct-to-garment (DTG) printing, pretreatment is a crucial step in the entire process. DTG pretreatment enhances the fabric's ink absorption, ensures sharp image clarity, and boosts colorfastness. For 100% cotton or cotton-polyester blends, such as t-shirts, jerseys, and hoodies, proper pretreatment is fundamental for achieving high-quality prints with a DTG printer.

Why is DTG Pretreatment Necessary?

In DTG printing, pigment ink is commonly used for its eco-friendly properties, fabric compatibility, and ability to produce vibrant designs. Popular fabrics for DTG garment printer include cotton and cotton-polyester blends. Pretreatment involves a series of steps, but the most critical one is applying the pretreatment liquid.

The DTG pretreatment liquid typically consists of water-based polymers that, when applied to the fabric, provides the following benefits:

1. Improved Pigment Ink Adhesion: Strengthens the bond between the pigment ink and the fabric surface, ensuring the ink stays in place.

2. Enhanced Image Sharpness: Fills the gaps and pores of the fibers, reducing ink bleeding and diffusion, resulting in clear edges and sharp details.

3. Brighter Colors: Contains additives that evenly distribute the pigment ink, boosting color vibrancy and saturation.

4. Increased Colorfastness: Improves the garment's resistance to washing and abrasion, ensuring the printed design remains vibrant and durable.

DTG Pretreatment Steps and Machines

A complete pretreatment for DTG printing process involves the following steps:

1. Fabric Cleaning

● Removing Dust and Oil Residues: Blank T-shirts or hoodies often have dust, oil, or residues left from production, which can affect ink adhesion. Proper cleaning removes these impurities to ensure better print quality.

● Removing Softeners and Chemicals: Some fabrics are treated with softeners or other chemicals during production, which can hinder pretreatment solution absorption. Thorough cleaning eliminates these residues.

2. Degreasing

Cotton and cotton-polyester fabrics may contain trace amounts of grease, particularly in polyester fibers. This can reduce the pretreatment liquid's and ink's adhesion.

Degreasing with mild alkaline detergents or degreasers effectively removes these oils, preparing the fabric for optimal printing results.

3. Surface Fuzz Removal

For knit fabrics, surface fuzz can interfere with print clarity.

To improve print quality, heat presses or de-fuzzing machines are often used to remove surface fibers through heat or mechanical friction, creating a smooth print surface for sharper, more detailed images.

4. Applying Pretreatment Liquid

Spraying machines are a common type of DTG pretreatment machine, particularly suitable for large-scale garment processing. They work by evenly spraying the DTG pretreatment liquid onto the fabric surface through multiple nozzles, creating a fine mist.

5. Drying

Common industrial drying equipment includes tunnel dryers and high-temperature drying machines. These use circulating hot air to evaporate excess DTG pretreatment liquid from the fabric surface, quickly drying the treated material.

The drying process ensures the removal of excess moisture and chemicals, further improving ink adhesion and colorfastness.

After pretreatment, factories can then use a DTG printer to directly print onto the treated garments or cut pieces.

For dark or black fabrics, white ink underbase is required before digital printing. The white underbase provides a bright and uniform foundation for the subsequent color inks, ensuring vibrant image reproduction on dark substrates.

Optimize Your Workflow with HPRT Digital Fabric Printers

In the apparel, home textile, and other industries, selecting the right digital fabric printing machine is key to improving production efficiency and quality. HPRT provides professional DTG printers, roll-to-roll digital textile printers, dye sublimation textile printers, and associated pretreatment and post-treatment equipment and technical support to help clients build high-quality, high-efficiency fabric printing production lines.

For purchasing or technical inquiries, please feel free to contact us.