DTG Pretreatment Explained: When and How to Pretreat
DTG pretreatment explained for apparel shops: when lights and darks need it, spray vs machine basics, dry and cure order, and common pretreat faults.
Brand-neutral DTG pretreat guide: when you need it, how to apply and dry it, and fixes for marks, stiff hand and cracking.
DTG pretreatment is a liquid applied to the print area and dried before direct to garment printing so the ink, especially white ink on dark garments, sits on the fabric surface and bonds instead of soaking in; dark cotton garments printed with white ink need it, light garments printed with color only often do not, and the drying step is commonly run on a heat press at roughly 320 to 356°F until the garment is fully dry, following the pretreat and ink maker's spec.
Pretreat rule: pretreat prepares cotton and cotton-rich garments so white and color inks bond and stay bright, especially on darks. Use the formula the pretreat maker specifies for lights or darks, apply evenly, dry fully, then print, cure and wash-test a sample before a production run.
Part of the DTF guides in the DAX Learning Hub, where DTG topics sit alongside DTF for now. For choosing between methods, see DTF vs DTG vs Screen Printing and Which Decoration Method to Start With; this page does not compare methods.
What DTG Pretreatment Does
DTG inks are water-based pigment inks. Without pretreat, white ink on a dark shirt wicks into the fibers and looks dull and patchy. Pretreat holds the ink on the surface, helps it bind, and contributes to wash fastness after the print is cured. Pressing the pretreated area also flattens loose fibers so the print surface is smoother.
When You Need Pretreat (Lights, Darks, Blends)
| Garment | Typical pretreat need | Notes |
|---|---|---|
| Dark cotton, printed with white ink | Needed | White underbase needs pretreat to sit on top and bond |
| Light or white cotton, color ink only | Often optional | Some shops still pretreat lights for brightness and wash results; follow the ink maker |
| Cotton-rich blends | Depends on blend and chemistry | Many systems call for a higher cotton share; test first |
| Polyester and performance fabrics | Often outside standard DTG workflows | May need different chemistry or a different method; see dye migration risk |
DTG generally suits 100% cotton or garments with a cotton-rich print face. For polyester issues such as dye bleeding through light inks, see Dye Migration on Polyester.
Spray vs Pretreat Machine Basics
Pretreat can be applied with a hand sprayer or a pretreat machine. Hand spraying costs little up front but depends on operator technique, and uneven coverage shows up as patchy prints or visible marks. Machines apply a more repeatable layer and suit higher volume. Some shops roll the wet area after spraying to even it out. Either way, the right amount depends on the garment weight, color and chemistry, so follow the maker's guidance and test.
How to Pretreat a Garment for DTG Step by Step
- Confirm fabric and color. Check fiber content and whether the design needs white ink.
- Choose light or dark pretreat as required. Use the formula the pretreat maker specifies for that garment color.
- Apply evenly. Cover the full print area plus a small margin with an even wet layer by sprayer or machine.
- Dry to the chemistry spec. Many makers publish heat press starting points around 320 to 356°F, pressing until the garment is completely dry (often 20 to 40 seconds, sometimes repeated). Follow the pretreat maker's pressure guidance (published specs range from light to firm pressure).
- Print. Load the garment flat; on darks the printer lays white first, then color.
- Cure. Cure the ink to the ink maker's time and temperature with a heat press or dryer.
- Wash-test a sample. Wash one piece per care instructions before running the order.
Drying, Printing and Curing After Pretreat
Pretreat must be fully dry before printing; damp pretreat leads to poor white coverage and weak bonding. After printing, the ink still needs a full cure; under-cured or over-cured prints can lose wash durability. Press and dryer readouts can drift, so verify actual temperature with a suitable thermometer or probe. The test-and-verify mindset in How to Cure Plastisol Ink carries over, even though DTG cure numbers come from the ink maker.
Common Pretreat Problems (Bleaching, Stiff Hand, Cracking)
| Problem | Likely causes | Fixes to try |
|---|---|---|
| Visible box, stain or mark around the print | Too much pretreat, uneven spray, wrong formula for the color, garment dye that reacts | Even out application, trim the pretreat area, confirm light vs dark formula, test the blank; some marks wash out, confirm on a sample |
| Bleached or discolored area | Garment dye reacts with pretreat or heat | Lower the amount, test a different blank, follow the maker's guidance for that color |
| Stiff hand | Heavy pretreat or heavy ink laydown | Reduce to the minimum that gives good white coverage on a test |
| Patchy or dull white | Too little pretreat, uneven coverage, damp garment | Increase coverage evenly; dry fully; flatten fibers |
| Cracking or poor wash results | Under-cured pretreat or ink, wrong amount, poor blank | Verify cure temperature and time; adjust amount; wash-test |
Buying Pretreated Blanks vs Doing It In House
Some suppliers sell garments already pretreated for DTG. They save labor and equipment but limit you to the styles and colors offered and may need a quick re-press before printing; check storage guidance. In-house pretreat gives more control over amount and blank choice but adds a step, a drying station and a learning curve. Compare labor, waste and blank options before you decide. For sourcing and stocking blanks, see Wholesale Blanks Buying and Blank Inventory and Sizing.
Frequently Asked Questions About DTG Pretreatment (FAQ)
What is DTG pretreatment?
A liquid applied to the print area and dried before DTG printing so the ink, especially white ink, stays on the fabric surface and bonds instead of soaking in.
Do light shirts need pretreat for DTG?
Often not when you print color ink only with no white, though some shops pretreat lights for brightness and wash results. Follow the ink and pretreat maker's guidance and test.
Can you DTG without pretreat?
On light cotton with color only, often yes. On dark garments that need white ink, pretreat is generally required; without it the white soaks in and looks dull.
Why does pretreat leave a mark or bleach the shirt?
Common causes are too much pretreat, uneven application, the wrong formula for the garment color, or a garment dye that reacts. Reduce and even out the amount, confirm the formula and test the blank first.
Should I buy pretreated shirts or pretreat in house?
Pretreated blanks save labor and a step but limit style and color choice. In-house pretreat gives control but adds equipment and training. Compare total labor, waste and blank options for your order mix.
Temperatures, times and amounts in this guide are commonly published starting points, not universal settings. Figures vary by chemistry, ink, garment and equipment; check the supplier spec before production.
Pretreat results are easier to judge when you can see sprayers, machines and printed samples side by side. Browse more guides in the DAX Learning Hub, and check cities and dates on the DAX show schedule when you are ready to compare DTG workflows with suppliers in person.