Screen Exposure Planning
A sharp stencil needs measured exposure, not guesswork. Light output changes with distance, lamp age, glass, filters, and coating thickness. This calculator turns those items into one exposure time. It also estimates whether a requested line or dot can survive the screen mesh.
Why Energy Matters
Exposure is energy delivered to the emulsion. Irradiance gives the power per square centimeter. Time completes the dose. When distance increases, power drops quickly. A small height change can alter exposure more than expected. That is why the inverse square correction is included. Transmission and lamp output percentages reduce the usable energy reaching the stencil.
Resolution Limits
Resolution is controlled by several physical limits. Mesh pitch sets the repeated support pattern. Thread diameter blocks part of each opening. Thick stencil layers can close fine details. Contact gaps create light spread at image edges. The calculator combines these limits and returns a practical minimum feature estimate. It also compares that estimate with the desired line width.
Using the Result
Use the suggested time as a starting exposure. Then confirm it with a step wedge, washout check, and print test. The result is most useful when the lamp irradiance is measured with a meter. If no meter is available, enter a known exposure value as a target and keep the same setup geometry.
Advanced Workflow
For production work, save each result with mesh type, emulsion name, coating method, and room conditions. Repeat the measurement after replacing bulbs or changing vacuum glass. Compare exported records to find drift. Stable records make repeats faster and reduce wasted screens.
Practical Notes
A safe exposure usually keeps fine lines open while fully hardening background areas. Underexposure may cause slimy washout, weak shoulders, and early stencil breakdown. Overexposure may close small text and halftone dots. Balance both sides. Record humidity, dryer time, and mesh tension, because they often change edge strength too.
Final Advice
Treat every number as an engineering estimate. Real emulsions vary by brand and batch. SAATI materials also depend on coating, drying, and storage. Use this calculator to narrow the range, then let controlled test strips choose the final production exposure.