What is print cracking?#
Print cracking is the breaking up of a printed layer (screen print ink or heat transfer) into cracks when the garment is stretched, worn or washed. In worse cases, pieces of the print flake or peel away. It is common on plastisol and water-based prints on stretchy knits, and on heat transfers applied with the wrong settings.
Some designs use a deliberate cracked or distressed look. Those are approved against a standard; unplanned cracking is a defect.
What it looks like#
- Fine cracks across the print when the fabric is stretched.
- Cracks that get larger after washing.
- Flaking or peeling at the edges of the print.
- A stiff, brittle feel to the print.
Where it occurs#
- Large solid prints on T-shirts and sweatshirts.
- Stretch fabrics such as elastane jersey and sportswear.
- Heat transfers and vinyl on knits.
- Fabrics with silicone softeners that reduce adhesion.
Likely causes#
A print must bond to the fabric and stretch with it. Under-cured ink is weak and cracks or washes off. Ink that stretches less than the fabric cracks under stress. A thick deposit is stiffer and cracks more easily. Surface finishes can stop the ink from bonding.
Machine-related causes#
- Under-curing: dryer temperature too low, belt too fast, or uneven heat.
- Heat press settings wrong for transfers: temperature, time or pressure.
Material-related causes#
- Ink type not designed for stretch fabrics.
- Fabric finishes, especially silicone softeners, reducing adhesion.
- Fabric with high stretch where the print covers large areas.
Operator and process-related causes#
- Heavy ink deposits from extra strokes or coarse mesh.
- Skipping flash curing between colors where needed.
Method-related causes#
- No stretch and wash test on bulk printed garments.
- Artwork with large solid areas on stretch garments without a soft or stretch ink system.
How to confirm the cause#
- Stretch test: stretch the printed area and look for cracks; compare with an approved sample.
- Wash test printed garments to the buyer's method and inspect the print.
- Measure cure: use temperature strips or probes to check the ink film reaches the ink supplier's curing temperature for the required time.
- Check adhesion with a tape test or the buyer's specified method.
- Print on fabric without softener to see if adhesion improves.
Immediate containment#
- Stop printing and check the dryer or press settings.
- Stretch and wash test garments already printed.
- Separate garments with cracking; re-curing may help under-cured prints if done correctly and tested.
Corrective action#
| Cause | Corrective action |
|---|---|
| Under-curing | Correct dryer temperature and belt speed; verify with cure test |
| Wrong ink | Change to stretch ink system for the fabric |
| Thick deposit | Adjust mesh, squeegee and strokes |
| Adhesion blocked by finish | Change fabric finish or use a suitable adhesion system |
| Heat press settings | Set to transfer supplier's specification |
Preventive action#
- Print strike-off approval including stretch and wash tests.
- Cure verification at the start of each shift and after changes.
- Ink selection matched to fabric type and stretch.
- Fabric finish agreed with the printer before fabric production.
Inspection notes#
- Stretch-check prints at inline and final inspection, as the buyer's manual allows.
- Print cracking after washing is found by testing; keep test reports by style and batch.
- Cracking or peeling is normally a major defect unless the design is intentionally distressed.
Example investigation#
A large chest print on a cotton-elastane T-shirt cracks after one wash. The same print on 100% cotton does not. Cure tests show the ink reaches the correct temperature. The elastane fabric has a silicone softener finish, and a tape test shows weak adhesion. The printer switched to an ink system with an adhesion promoter for that fabric, and the strike-off was retested after washing before bulk printing resumed.
Questions to ask the print supplier#
- Which ink system is used, and is it rated for stretch fabrics?
- What curing temperature and time does the ink supplier specify, and how is it verified?
- How often are dryer temperatures checked, and at which belt positions?
- Has the print been tested on this exact fabric, including its finish?
- What wash and stretch tests are done on each production batch?
Factory checklist#
- Ink system suited to the fabric's stretch
- Cure temperature and time verified each shift
- Ink deposit controlled
- Fabric finish compatible with printing
- Stretch and wash tests on strike-offs and bulk
Related guides: poor rubbing fastness, color bleeding.