Technical Tuesday-Get Your Exposure Times Dialed Back In!

Is Your Screen Exposure Ghosting You? Time for a Reality Check!

I’ve spent the last couple of weeks visiting shops and troubleshooting production issues, and there’s a recurring theme: off-base exposure times. It’s easy to set your timer once and forget it, but I’m seeing screens fail in the washout booth more than they should. If you haven’t tested your exposure in the last month, consider this your sign to dial it back in.

The "Why": Why "Set it and Forget it" is a Myth

Think of your exposure unit like a high-performance engine; even the best ones need a tune-up. Your exposure time isn't a static number because the world around your screen is constantly shifting.

• Environmental Shifts: High humidity is a screen room villain. Moisture trapped in the emulsion can scatter UV light, forcing you to need longer exposure times just to get the same results.
• Equipment Aging: Whether you’re using metal halide or modern LEDs, light sources weaken over time. What took 30 seconds last year might take 40 seconds today.
• Raw Material Variables: Manufacturers occasionally update emulsion formulas or experience raw material changes that can slightly alter how the product reacts to light.

The "How": Dialing it in Like a Pro

To stop guessing and start printing, you need to use a Stouffer 21-Step Transmission Scale. It’s the industry-standard "thermometer" for your screen.

1. The Stouffer Test: Tape a 21-step scale directly to the glass of your exposure unit (or to the screen if using a Computer-to-Screen/CTS system).
2. Aim for a Solid Step 7: After exposing and washing out the screen, you want to see a "solid" step 7 remaining. This indicates a fully cured stencil that won't break down mid-run.
3. Weekly Maintenance: If you use CTS, tape the scale to a screen of a different mesh count once a week. Different mesh colors (white vs. yellow) and counts change how light is absorbed.
4. The Calculator Shortcut: Use an exposure calculator (a film with different opacity percentages) to run a single test that reveals your optimal time in one shot.

The Result: Peace of Mind in the Washout Booth

When your exposure is dialed in, the "chaos" of the screen room disappears. You’ll see:

• Vibrant Detail: High-resolution halftones that actually stay on the mesh instead of washing away.
• Production Speed: No more re-burning screens because the stencil blew out on the press.
• Consistency: A predictable workflow where every screen performs exactly like the one before it.

Ready to stop the guesswork? We have exposure calculators available to help you find your perfect number. Reach out if you need help reading your steps—let's get those screens locked in!

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