Screen Printing Troubleshooting Tips

From exposure to washout, we offer a detailed list of common screen printing problems below, along with possible solutions. For a free printable Troubleshooting Guide, click here.

Washout Breakdown—Adhesion Loss During Developing

Poor Coating Methods

Check user's guide for coating instructions. Use proper scoop coater.

Pre-Exposed or Outdated Film or Emulsion

Use yellow or subdued lighting in screen making area; dry screen in total darkness. Check lot number on packaging.

Screen Not Dry Enough for Exposure

Follow drying directions. Dehumidifier recommended in drying area.

Transfer Emulsion Has Inadequately Sensitized Film

After coating with transfer emulsion, allow about 10 minutes to elapse (dwell time) before placing screen into dryer or in front of a fan.

Improper Adhesion of Capillary Film

Use Chroma/Brade to abrade new mesh. Degrease properly with Chroma/Clean. Use wetting agent, such as Chroma/Wet.

Water Temperature Range Too Hot

90 to 100 degrees F (32 to 38 degrees C) optimum water temperature.

Excessive Water Pressure and/or Washing

Decrease water pressure and/or time of washout.

Inadequate or Inconsistent Exposure

Use Chromaline Exposure Calculator to determine proper exposure time and light source performance.

Contaminated Mesh

Use Chroma/Brade to abrade new mesh, especially when using film. Degrease properly with Chroma/Clean degreaser.

Washout Difficult—During Developing

Poor Positive

Check density or image quality; emulsion of positive should be in contact with stencil emulsion.

Pre-Exposed or Outdated Film or Emulsion

Use yellow or subdued lighting in screen making area; dry screen in total darkness. Do not use outdated material.

Excessive Heat Used in Drying Screen

Do not exceed 110oF (43oC). Chromaline recommends 85o to 95oF (30o to 35oC). A dehumidified drying cabinet is best.

Overexposure

Shorten exposure; run an exposure test.

Pinholes

Powdered Sensitizer

Be sure powder is completely dissolved before mixing with emulsion.

Emulsion Coating Too Thin

Apply additional coats on print side after drying; or use higher solids emulsion.

Film Too Thin for Mesh

Check user's guide for correct film thickness and mesh selection.

Air Bubbles in Emulsion

Allow emulsion to settle a minimum of two hours after sensitizing; allow additional setting time if emulsion is re-blended.

Dirt or Grease on Mesh

Degrease mesh properly, using Chroma/Clean degreaser.

Underexposure

Use Chromaline Exposure Calculator to determine proper exposure time and light source performance. Feel squeegee side of stencil during wash out. If it feels slimy or you get color on your fingers, screen is underexposed.

Dust and Shop Dirt

Shop cleanliness. Clean artwork, film and vacuum frame glass prior to use. An anti-static brush or cloth is recommended.

Scumming or Haze

Light Scatter

Use dyed or tinted fabric or reduce exposure.

Pre-Exposure of Film or Emulsion

Use yellow or subdued lighting in screen making area; dry screen in total darkness.

Poor Positive and Contact

Check quality of positive. Check vacuum frame for complete contact in all areas of screen.

Excess Moisture in Screen Making Area

Use dehumidifier to maintain 50 to 70 percent relative humidity.

Incomplete Washout and/or Under Exposure (a major common problem)

Increase exposure and/or washout until foaming stops. Use a wet vac to suck out the water and scum.

Weak Stencil

Stencil Too Thin for Mesh

Check user's guide for film/emulsion recommended for mesh count.

Baggy Mesh

Use tension recommended by mesh manufacturer.

Screen Not Fully Dry During Exposure

Follow drying instructions. Dehumidifier recommended in drying area.

Emulsion Coating Too Thin

Apply additional coats on print side after initial drying; or use higher solids emulsion.

Film Too Thin for Mesh Count

Check user's guide for proper film thickness.

Underexposure (the most common cause of stencil failure)

Increase exposure time. **Use Chromaline Exposure Calculator to determine proper exposure time and light source performance. Feel squeegee side of stencil during washout. If it feels slimy or you get color on your fingers, screen is underexposed. **Pure photopolymer and dual cure stencil systems may be post-exposed after complete drying for increased durability.

Poor Image—Sawtooth

Poor Positive to Screen Contact

Check vacuum frame for complete contact in all areas of screen.

Undercutting

Use dyed or tinted fabrics. Decrease exposure time.

Incorrect Drying of Emulsion

When drying, place coated screen in horizontal position, print side down.

Stencil Too Thin

Film Users: use thicker film. Emulsion Users: use more coats or thicker emulsion on the print side.

Inconsistent Light Exposure

Use point light source with light integrator for best results. Check bulb age.

Incorrect Exposure

Use Chromaline Exposure Calculator to determine proper exposure time and light source performance.

Undercutting

Placement of Positive

Emulsion of positive should be in contact with print side of screen.

Light Scatter Within Mesh
Use dyed or tinted fabrics. Increase exposure time 25 - 100 percent.
Inconsistent Exposure to Light

Use point light source with light integrator for most uniform exposure.

Improper Exposure

Use Chromaline Exposure Calculator to determine proper exposure time and light source performance.

Poor Contact of Positive to Screen

Check vacuum frame for complete contact in all areas of screen.