Troubleshooting

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General guidance. Your ink, emulsion and chemical makers' directions come first.

Pinholes

Small dots of open mesh that print where they shouldn't.

Common causes

Dust, lint or debris on the screen, film or exposure glass
Emulsion coated over dirty or poorly degreased mesh
Underexposure leaving the stencil weak
Air bubbles in the emulsion

Try

Degrease mesh and let it dry in a clean, dust-free area
Clean the film and glass before exposing
Check exposure with an exposure test (your emulsion maker's method)
Block small pinholes with screen filler or blockout tape before printing

Ghosting / ghost image

A faint image of an old design that remains in the mesh after reclaim.

Common causes

Ink or emulsion residue stained into the mesh
Ink left to dry in the screen
Reclaim chemicals not fully rinsed or left to dry on the screen

Try

Clean ink out promptly after the run
Use a haze/ghost remover per its directions after reclaim
Rinse thoroughly with water; follow chemical dwell times

Bleeding

Ink spreads past the edges of the design, giving fuzzy or fat edges.

Common causes

Too much squeegee pressure or too many strokes
Ink too thin or too warm
Off-contact too low
Mesh too coarse for the detail
Water-based ink migrating on absorbent fabric

Try

Use less pressure and fewer strokes
Check off-contact and set per your press setup
Use a higher mesh for fine detail
Avoid over-reducing the ink

Fibrillation

Fibers poke up through the ink after printing or washing, making the print fuzzy or speckled.

Common causes

Loose fibers on the garment surface (common on lower-twist or heavily napped fabric)
Thin ink deposit that can't lock fibers down
Underbase not flattened

Try

Print-flash-print the underbase so fibers get locked down
Use a smoothing/flattening screen or heat press on the underbase where appropriate
Use a slightly heavier deposit or a lower mesh for the underbase
Try a smoother, ring-spun garment if possible

Poor cure

Print cracks when stretched, feels tacky, or washes out.

Common causes

Ink film never reached the maker's cure temperature
Dwell too short or dryer belt too fast
Thick deposit not heated all the way through
Dryer setting read instead of actual ink temperature

Try

Measure ink film temperature with a probe or temp strips
Slow the belt or raise heat within the ink maker's guidance
Stretch and wash test samples before running
See the Cure Temp Guide on this site

Stencil breakdown

Emulsion wears, peels or washes out during printing.

Common causes

Underexposure (stencil not fully hardened)
Poor degreasing before coating
Screen not fully dry before exposure
Emulsion not suited to the ink (e.g. plastisol-only emulsion with water-based ink)

Try

Run an exposure test and expose fully
Degrease and dry the screen completely before coating and exposing
Use an emulsion rated for your ink; some need post-exposure or hardener for water-based
Follow your emulsion maker's storage and coating directions

Moiré

A visible wavy or checkered pattern in halftone prints.

Common causes

Halftone frequency (LPI) interfering with mesh count
Halftone angle lining up badly with the mesh threads
Mesh stretched at an angle or film placed crooked

Try

Choose an LPI that suits your mesh (see the Mesh & LPI Chart)
Try a different halftone angle (many printers start around 22.5°)
Keep film square to the mesh when exposing

Dye migration

Dye from a polyester garment bleeds into the ink, e.g. a white print turning pink on red poly.

Common causes

Polyester dyes turn to gas (sublimate) under heat
Curing hotter or longer than needed
Using ink not designed for polyester

Try

Use a low-bleed or low-cure ink made for polyester
Use a bleed-blocker underbase where recommended
Cure at the lowest temperature the ink maker allows
Test a sample and let it sit; migration can appear hours later