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Fix a problem · 4 of 5 · 7 min read

On-press problems

Bleeding, feathering and dot gainEdges spread and look soft or furry, small dots swell and halftones go dark, and ink shows inside the shirt.
Looks like
Edges spread and look soft or furry, small dots swell and halftones go dark, and ink shows inside the shirt. (Printers also say “bleeding” for dye migration; that’s a different problem: see Dye migration.)
Likely causes
  • Too much squeegee pressure
  • Ink too thin
  • A squeegee too hard for the job
  • Open, loose-weave fabric
  • Too little print-side emulsion to act as a gasket
  • Squeegee angle outside the usual 45–60° from the screen (Avient)
  • Wiping the bottom of the screen mid-run
Fix it now
Lower the pressure until it almost won’t print, then add just enough to print cleanly (Impressions). Stir the ink rather than thinning it. Try a sharper edge.
Stop it next time
Coat screens with a proper print-side layer, use finer mesh for detailed art, and check dot gain with a halftone test strip and a loupe.
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Presses & setup
Sources: Impressions · Screen Printing Magazine · Avient
Double image or shadow printA second, offset copy of the print, or a smear trailing in the squeegee direction.
Looks like
A second, offset copy of the print, or a smear trailing in the squeegee direction.
Likely causes
  • The shirt lifting or shifting: not enough platen adhesive, or adhesive killed by flash heat
  • Loose screen clamps or print heads
  • Low tension or too little off-contact, so the screen drags the shirt
  • A second stroke after the shirt moved
Fix it now
Refresh the adhesive (Impressions says most water-based adhesives hold up better under the flash than aerosols), tighten clamps, and raise off-contact a little.
Stop it next time
Use tight screens, keep clamps snug, check adhesive often during a run, and set proper off-contact.
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Presses & setup
Sources: ScreenPrinting.com Help · Impressions · Ink Kitchen
MisregistrationGaps between colors, underbase peeking out, or one color shifted or rotated.
Looks like
Gaps between colors, underbase peeking out, or one color shifted or rotated.
Likely causes
  • Mismatched or low screen tension (one of the most common)
  • Platen adhesive failure (one of the most common)
  • Worn press shafts and bearings, loose clamps, platens out of level
  • Over-flashing that shrinks some fabrics
  • Bad films or poor film contact
  • Warped frames, thin ink, operator error
Fix it now
Read the pattern (see the diagram), match it to its cause, and re-check level and clamps. Don’t hammer the micro-adjusters.
Stop it next time
Use good films, burn screens straight and centered, keep all screens in a job at similar tension (at least 20 N/cm, 25 is better, per ScreenPrinting.com), maintain the press, and use a registration system.
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Presses & setup
Evenly off one wayOff at the bottomWrong size all roundRotated
Reading a misregistration (our own simplified drawing, after Screen Printing Magazine’s registration figure). Solid: the first color. Dashed: the color that’s off. Left to right: evenly off one way, off at the bottom, wrong size all round, rotated.
  • Evenly off in one direction: fix it with the micro-adjusters.
  • Off only at the bottom: the screen may be stretching.
  • Too big or too small on every side: the art or film was output at the wrong size.
  • One corner off: the press may be out of level, or the shirt moved.
  • Underbase showing at the edges: the art needs a choke or trap.
  • Rotated: the image was burned crooked on the screen.
Sources: Screen Printing Magazine · Ink Kitchen · Impressions · ScreenPrinting.com Help · ScreenPrinting.com
Mesh marks or orange peelA fine grid texture in solid areas (the mesh printed into the ink), or a bumpy orange-peel surface.
Looks like
A fine grid texture in solid areas (the mesh printed into the ink), or a bumpy orange-peel surface.
Likely causes
  • Too little off-contact, so the screen doesn’t snap away
  • Low tension
  • A thin print-side stencil (thicker emulsion acts as a gasket)
  • Ink too thick to level out
Fix it now
Raise off-contact a bit, use tighter screens and stir the ink. If you reduce it, use a curable reducer at the maker’s dose; Davis warns that non-curable reducers and mineral spirits can stop plastisol from fusing.
Stop it next time
Use proper tension and print-side emulsion thickness. A heat-press smoothing step after cure can also flatten texture (see fibrillation).
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Presses & setup
Sources: Impressions · Davis International · Avery Dennison · PrintWiki
Fibrillation (fuzzy prints)Tiny fibers poke up through the ink so the print looks fuzzy or dull, often worse after the first wash.
Looks like
Tiny fibers poke up through the ink so the print looks fuzzy or dull, often worse after the first wash. Most noticeable with large dark prints on light shirts (Lawson).
Likely causes
  • Fiber-prone blanks (cotton and tri-blends more than 100% polyester jersey, per Avient)
  • A thin ink layer
  • Too much pressure, driving ink into the shirt instead of onto it
  • Squeegee laid back too far (a low angle to the screen)
  • A thin stencil gasket
  • The screen sticking to the shirt from low off-contact or tension
Fix it now
Print, flash, and print again over a flattened first layer; Texsource describes “flash and smash” (a blank screen and hard squeegee over the flashed base). Fujifilm calls flashing a groundcoat the most effective fix; Lawson suggests a primer or clear topcoat. After cure, ScreenPrinting.com suggests smoothing with a heat press and a smooth sheet (its example: about 270°F, light-to-medium pressure, 5 seconds, for an ink that cures at 320°F). That’s for smoothing a print that’s already cured, not for curing. Check your ink’s tech data sheet. Fibrillation or undercure? Fujifilm’s test: re-cure half the print per the TDS, wash both halves; if the re-cured half isn’t clearly better, it’s fibrillation.
Stop it next time
Pick less fiber-prone blanks where the job allows, use a coarser mesh for more deposit, don’t over-thin ink, and use a squeegee angle in Avient’s 45–60° range for manual printing (measured from the screen). On light shirts, water-based ink colors the fibers so strays show less.
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Inks
Sources: Lawson Screen & Digital · Texsource · Fujifilm · ScreenPrinting.com Help · Avient
Poor opacity on dark shirtsWhite looks gray or speckled, colors look dull and muddy on black, and the shirt shows through.
Looks like
White looks gray or speckled, colors look dull and muddy on black, and the shirt shows through.
Likely causes
  • Too little ink deposit: mesh too fine, squeegee too hard, or too much pressure
  • Ink not made for darks
  • No underbase
  • Davis: opacity depends on ink type, deposit, fabric and cure method
Fix it now
Print, flash, print again. Try a softer squeegee and flood before every print so ink sits on top of the shirt.
Stop it next time
Use a white underbase for multi-color art on darks, a lower mesh for opaque whites (Avient charts underbase whites around 110–160), and a high-opacity ink. Don’t reduce low-bleed or poly whites (Avient).
More
Art & separations
Sources: Davis International · Impressions · Avient · ScreenPrinting.com Help
Ink drying in the screenFine detail stops printing partway through a run, the print gets blotchy, or the mesh clogs.
Looks like
Fine detail stops printing partway through a run, the print gets blotchy, or the mesh clogs. Most common with water-based and discharge.
Likely causes
  • Water-based ink evaporating in open mesh during pauses
  • Fans blowing across the press
  • Plastisol partly curing where the screen touches a hot, just-flashed print
Fix it now
Water-based ink can often be reopened with a damp rag or a mist of water. A clogged plastisol screen needs press wash.
Stop it next time
Keep the screen flooded between prints, avoid breaks with ink open in the screen, keep fans off the press, and let flashed prints cool a moment.
More
Inks
Sources: Impressions · ScreenPrinting.com · Signs101 forum · ScreenPrinting.com Help
Ink build-up on the back of the screenIn multi-color work, ink from earlier colors collects under later screens and prints back as smudges, halos or a rough texture.
Looks like
In multi-color work, ink from earlier colors collects under later screens and prints back as smudges, halos or a rough texture.
Likely causes
  • Mesh too coarse, laying down too much ink
  • Loose screens
  • Color order (for example black in the middle of the sequence)
  • Sticky ink; heat makes plastisol stickier
  • Heavily trapped art
  • On-contact printing, or so much off-contact it needs heavy pressure
  • Squeegee and flood speeds not matched
Fix it now
Wipe the back of the screen with press wash during the run.
Stop it next time
Tighter screens, finer mesh, sharp blades, lighter pressure, a smooth flood, a flash between layers where needed, and light colors before dark (Lawson). Anti-build-up additives exist; follow the TDS.
More
Presses & setup
Sources: Lawson Screen & Digital · Lawson Screen & Digital · Screen Printing Magazine · Screen Printing Magazine
Sources for this guide (50)
  1. ScreenPrinting.com Help, Pinholes and fisheyes
  2. Chromaline, Causes of pinholes during screen making
  3. Chromaline, Underexposed screen tech tip (PDF)
  4. Avery Dennison, IB 8.34 silkscreen troubleshooting guide (PDF)
  5. ScreenPrinting.com Help, Over- vs. under-exposure
  6. ScreenPrinting.com Help, How do I figure out exposure times?
  7. ScreenPrinting.com Help, Why can’t I burn my screens correctly?
  8. ScreenPrintingNow, Using the 21-step wedge
  9. Lawson Screen & Digital, Direct emulsion troubleshooting checklist
  10. Avient, Print technique guide, 2023 (PDF)
  11. Chromaline, 10 common reasons for stencil breakdown on press
  12. ScreenPrinting.com, Printing with plastisol vs. water-based ink
  13. ScreenPrinting.com, Get rid of ghost images
  14. ScreenPrinting.com Help, How do you reclaim screens?
  15. Screen Printing Magazine, Preventing and removing haze
  16. International Coatings, Preventing moiré patterns
  17. Screen Printing Magazine, Ten tips to help avoid halftone moiré
  18. Solutions for Screen Printers, Halftone angles demystified
  19. Impressions, Troubleshooting screen printing (2018)
  20. Screen Printing Magazine, Catching the on-press culprit
  21. ScreenPrinting.com Help, Why is my print fuzzy?
  22. Ink Kitchen, Why out of register? Let me count the ways
  23. ScreenPrinting.com Help, What’s considered good mesh tension?
  24. ScreenPrinting.com, Registering water-based and plastisol prints
  25. Davis International, Common issues
  26. PrintWiki, Mesh marks
  27. Lawson Screen & Digital, Eliminating fibrillation
  28. Texsource, What is fibrillation?
  29. Fujifilm, Fibrillation in plastisols (PDF)
  30. ScreenPrinting.com Help, How do I pick the right mesh count?
  31. ScreenPrinting.com, High contrast with discharge inks
  32. Signs101 forum, Just started screen printing again
  33. ScreenPrinting.com Help, Water-based vs. plastisol
  34. Lawson Screen & Digital, Plastisol ink FAQ
  35. Lawson Screen & Digital, Reducing plastisol ink build-up
  36. Screen Printing Magazine, Anti-build-up additive
  37. PIA/SPTF, Textile plastisol curing troubleshooting (PDF)
  38. Lawson Screen & Digital, Curing plastisol inks
  39. ScreenPrinting.com Help, Why does ink crack in a stretch test?
  40. ScreenPrinting.com Help, Why does ink look faded after washing?
  41. Screen Printing Magazine, Curing comes clean through wash testing
  42. International Coatings, How do I test to make sure my inks are properly cured?
  43. ScreenPrinting.com, What is dye migration?
  44. ScreenPrinting.com, Decoding poly white and dye blocker inks
  45. Lawson Screen & Digital, Testing polyester for dye migration
  46. Lawson Screen & Digital, Low-cure screen printing ink
  47. Ink Kitchen, Scorching heat, scorching shirts
  48. ScreenPrinting.com Help, Can you over-cure plastisol ink?
  49. Screen Printing Magazine, Figuring out flash-curing parameters
  50. Wilflex (Avient), Ink curing tips (2020, PDF)

Where sources disagree, the page says so.