Few things are more frustrating than exposing a screen, washing it out, holding it up to the light, and seeing tiny unwanted openings in the stencil.
Sometimes they look like little dots.
Sometimes they look like small round craters where the emulsion seems to have pulled away from the mesh.
Sometimes you do not even notice them until ink starts showing up where it does not belong during production.
These problems are usually called pinholes and fisheyes.
They are common screen printing headaches, especially for newer printers, but they can also show up in experienced shops when screen prep, coating, drying, or cleanliness starts slipping.
The good news is that pinholes and fisheyes are usually preventable.
The key is understanding what they are, what causes them, and how to build a better screen prep process.
What Are Pinholes?
Pinholes are tiny unwanted openings in the emulsion stencil.
They allow ink to pass through the screen in places where ink should not print.
Pinholes may show up as:
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Tiny dots in the stencil
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Small light leaks when holding the screen up to light
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Little ink spots on the garment
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Random holes after washout
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Defects that appear during printing
A few small pinholes can often be blocked out before printing, but frequent pinholes usually point to a process problem.
Pinholes are commonly caused by dust, lint, debris, bubbles, coating issues, poor screen cleaning, or contamination.
What Are Fisheyes?
Fisheyes are small circular defects where the emulsion pulls away from the mesh.
They often look like round craters, rings, or open spots in the stencil.
Fisheyes are usually caused by contamination.
Common causes include:
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Oil
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Grease
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Silicone
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Adhesive residue
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Dirty mesh
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Improper degreasing
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Contaminated tools
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Touching mesh with bare hands
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Dirty water or washout areas
The reason they are called fisheyes is because the emulsion seems to repel away from the contaminated area, leaving a round open spot.
If pinholes are usually tiny random openings, fisheyes are more often a sign that something on the mesh prevented the emulsion from coating evenly.
Pinholes vs Fisheyes
Pinholes and fisheyes are related, but they are not always the same problem.
| Problem | What It Looks Like | Common Cause |
|---|---|---|
| Pinholes | Tiny random openings in the stencil | Dust, lint, debris, bubbles, poor coating, weak stencil areas |
| Fisheyes | Round craters or circular open spots where emulsion pulls away | Skipped Degreaser or not rinsed throughly, chemical, ink, oil, silicone, adhesive residue, contamination |
The difference matters because prevention starts with the cause.
If you have random tiny dots, you may need better cleanliness, coating technique, drying, or emulsion handling.
If you have round craters or repelled areas, you likely have contamination on the mesh or in your screen prep process.
Why Pinholes and Fisheyes Matter
Small stencil defects may seem minor until the job is on press.
Pinholes and fisheyes can cause:
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Unwanted ink dots
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Extra cleanup time
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More blockout work
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More tape usage
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Delayed production
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Reclaimed screens
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Missed deadlines
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Customer complaints
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Wasted shirts
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Frustration before the job even starts
A few minutes of better screen prep can save a lot of production time later.
A clean, consistent stencil makes printing easier.
A dirty or inconsistent stencil makes every step harder.
Common Causes of Pinholes
Dust and Lint
Dust is one of the most common causes of pinholes.
If dust lands on the screen before or during coating, it can block the emulsion from forming a clean film. After exposure and washout, that dust particle may leave a small open spot.
Common dust sources include:
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Dirty drying areas
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Open screen racks
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Lint from towels
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Cardboard dust
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Shop debris
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Dirty floors
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Fans blowing across coated screens
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Dusty storage areas
A screen room does not have to look dirty to create pinhole problems. Even small dust particles can cause defects.
Poor Degreasing
Degreasing is one of the most important steps in screen prep.
Mesh may look clean but still have oils, residue, or contaminants that affect emulsion adhesion.
Skipping degreasing or rinsing poorly can lead to:
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Pinholes
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Fisheyes
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Poor emulsion adhesion
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Stencil breakdown
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Uneven coating
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Random washout problems
Every screen should be properly degreased before coating, especially after reclaiming.
Dirty Scoop Coater
A dirty scoop coater can create coating defects.
Dried emulsion, dust, lint, or nicks in the coater edge can leave streaks, bubbles, or thin areas in the emulsion.
A damaged or dirty coater can create problems even if the screen itself was prepared correctly.
Keep scoop coaters clean, dry, and protected between uses.
Contaminated Emulsion
Emulsion can become contaminated if the bucket is left open, tools are dipped into it dirty, or dried emulsion flakes fall back into the container.
Contaminated emulsion can create:
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Bumps
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Debris
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Coating defects
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Pinholes
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Uneven stencil thickness
Always keep emulsion sealed when not in use, and avoid putting dirty tools into the container.
Air Bubbles in the Emulsion
Air bubbles can create small voids in the coating.
These bubbles may become pinholes after exposure and washout.
Bubbles can come from:
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Shaking emulsion
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Stirring too aggressively
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Coating too quickly
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Using emulsion too soon after mixing
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Pouring carelessly into the scoop coater
Let emulsion settle if bubbles are present.
Poor Coating Technique
Coating technique affects stencil quality.
Problems can come from:
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Coating too fast
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Uneven pressure
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Wrong scoop coater angle
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Starting and stopping unevenly
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Not enough emulsion
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Too much emulsion
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Thin spots
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Inconsistent coating passes
A weak or uneven stencil is more likely to develop pinholes or break down during printing.
Improper Drying
Coated screens need to dry in a clean, controlled environment.
If screens dry too slowly, too humid, or in a dirty area, problems can develop.
Poor drying can lead to:
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Soft emulsion
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Weak stencil
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Dust contamination
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Longer exposure times
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Poor washout
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Stencil breakdown
Screens should dry completely before exposure.
High Humidity
Humidity can cause major screen room problems.
If the emulsion does not dry properly, the stencil may remain soft, weak, or inconsistent.
High humidity can increase the risk of:
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Pinholes
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Poor exposure
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Difficult washout
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Stencil breakdown
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Sticky coated screens
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Longer drying times
A controlled drying area helps create more consistent screens.
Over-Washout
Sometimes pinholes appear or get worse during washout.
If the screen is underexposed, sprayed too aggressively, or washed too long, weak stencil areas can open up.
Over-washout can turn small defects into bigger problems.
Use proper exposure times and controlled washout pressure.
Common Causes of Fisheyes
Oil or Grease on the Mesh
Oil is one of the biggest causes of fisheyes.
It may come from hands, shop surfaces, equipment, dirty water, or residue left behind during reclaiming.
Even a small oily spot can repel emulsion and cause a circular defect.
Avoid touching clean mesh with bare hands.
Silicone Contamination
Silicone is a serious contamination problem.
It can come from sprays, lubricants, adhesives, softeners, or other shop products. Silicone can be difficult to remove and can cause repeated fisheye issues.
Keep silicone products away from the screen prep area.
Adhesive or Tape Residue
Old tape, pallet adhesive, spray adhesive, and other sticky residues can contaminate screens.
If residue is not fully removed during reclaiming and degreasing, it can interfere with emulsion coating.
Poor Rinsing After Chemicals
Chemicals left on the mesh can create coating problems.
After using stencil remover, haze remover, degreaser, or other screen chemicals, the screen should be rinsed thoroughly.
Chemical residue can affect emulsion adhesion and create fisheyes or other defects.
Touching the Mesh After Degreasing
Once a screen is degreased, avoid touching the mesh.
Hands can leave oil, lotion, dirt, or sweat behind.
If you handle screens after degreasing, hold the frame, not the mesh.
How to Prevent Pinholes and Fisheyes
Start With Proper Reclaiming
A good stencil starts with a clean screen.
Make sure old ink, emulsion, tape, adhesive, and residue are removed before the screen is reused.
Incomplete reclaiming creates problems later in the process.
Degrease Every Screen
Degreasing should not be optional.
Even new mesh and reclaimed screens can have contaminants.
Use a screen printing degreaser, scrub both sides of the mesh, rinse thoroughly, and dry the screen in a clean area.
A well-degreased screen is one of the best defenses against fisheyes.
Rinse Thoroughly
Do not leave chemical residue on the mesh.
After degreasing or reclaiming, rinse the screen completely.
Pay attention to corners, frame edges, and areas where chemicals can collect.
Dry Screens in a Clean Area
A dusty drying area can ruin good screen prep.
Keep coated and degreased screens away from:
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Fans blowing dust
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Open doors
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Cardboard dust
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Dirty floors
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Spray adhesive
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Shop traffic
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Lint-producing towels
A drying cabinet or clean screen rack can help reduce contamination.
Keep Scoop Coaters Clean
After coating, clean the scoop coater thoroughly.
Do not let emulsion dry on the edges.
Store the coater where the coating edge will not get scratched, bent, or contaminated.
A clean coater creates a cleaner stencil.
Handle Emulsion Carefully
Keep emulsion covered when not in use.
Avoid introducing dirt, dried emulsion flakes, or contaminated tools into the container.
If the emulsion has bubbles, let it settle before coating.
Improve Coating Technique
Use smooth, even pressure when coating screens.
Keep the scoop coater angle consistent.
Avoid rushing.
A consistent coating creates a stronger stencil and reduces weak areas.
Control the Drying Environment
Screens should be dry before exposure.
A controlled drying area helps prevent humidity-related problems.
If your shop struggles with humidity, consider airflow, dehumidification, and a drying cabinet.
Inspect Screens Before Exposure
Before exposing a screen, inspect the coated mesh.
Look for:
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Dust
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Bubbles
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Streaks
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Thin spots
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Fisheyes
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Coating defects
Catching problems before exposure can save time.
Inspect Screens After Washout
After washout and drying, hold the screen up to light and inspect it.
Small isolated pinholes can often be blocked out.
Larger problem areas may require reclaiming and starting over.
When to Block Out vs Start Over
Not every defect requires reclaiming.
Block out the screen when:
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There are only a few small isolated pinholes
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The image area is otherwise strong
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The defect is outside a critical print area
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The stencil is properly exposed
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The screen will hold up during production
Blockout can save a job when the screen is mostly good.
Start over when:
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There are many pinholes
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Fisheyes appear across the screen
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The emulsion is pulling away from the mesh
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The stencil feels soft or weak
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The image area is affected badly
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Defects repeat from screen to screen
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You suspect oil, silicone, or chemical contamination
If the screen has a contamination problem, blockout may only hide the symptom. It will not fix the cause.
Quick Prevention Checklist
Before coating and exposing screens, check:
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Screen fully reclaimed
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Mesh properly degreased
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Chemicals rinsed thoroughly
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Screen dried in a clean area
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Scoop coater clean and smooth
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Emulsion clean and bubble-free
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Coating pressure consistent
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Drying area clean and controlled
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Coated screen fully dry before exposure
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Screen inspected before exposure
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Screen inspected after washout
A simple checklist can prevent many common exposure headaches.
Final Thoughts
Pinholes and fisheyes are frustrating, but they are usually not random.
Most of the time, they point to dust, contamination, poor cleaning, coating problems, drying issues, or weak screen prep habits.
The solution is not only fixing the screen after the problem appears.
The better solution is building a process that prevents the problem in the first place.
Clean screens.
Clean tools.
Clean emulsion.
Good degreasing.
Controlled drying.
Careful coating.
Better inspection.
Those habits create better stencils, smoother production, and fewer headaches on press.
In screen printing, small details make a big difference.
And a clean stencil starts long before ink ever touches the shirt.
Need Help With Screen Prep?
KolorMatrix helps screen printers, startups, growing shops, schools, churches, and production teams improve their printing process with professional supplies, education, and support.
Whether you need degreaser, emulsion, scoop coaters, exposure equipment, screen room supplies, or help troubleshooting stencil problems, we are here to help.
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