How Long Should You Expose a Cyanotype? The Complete Guide to Stunning Blues
Whether you’re making your very first cyanotype with a starter kit or working on a large-scale artwork using our refill kit and professional accessories, the same question always comes up: How long should I expose my cyanotype for the best results?
The quick answer: there’s no one-size-fits-all timing. The real answer—where the magic happens—depends on light, materials, the season, and your artistic goals. Below, we break down the main factors that affect exposure time and share practical tips to help you achieve consistent, beautiful results.
1. Sunlight, UV lamp, or exposure frame – picking your light source
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Direct sunlight → Fast exposures (5–20 minutes on a bright summer afternoon).
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Overcast day → Slower (30–60 minutes) but often produces softer tonal transitions.
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UV lamp or exposure frame → Controlled, repeatable conditions—perfect for winter or night work. Our exposure frames let you fine-tune the process down to the minute.
2. Season and sun position
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Summer: Strong UV → shorter exposure.
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Winter: Weaker UV → longer exposure times needed.
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Tip: Use a UV meter app or check the weather report for UV strength.
3. Material and coating thickness
Thicker-coated paper or fabric can require more light time.
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Cotton: absorbs more sensitiser → slightly longer exposure.
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Smooth paper: more even absorption → faster, more consistent results.
With our cyanotype chemicals, you can tweak your coating mix and experiment to find your perfect formula.
4. The colour indicator – watching for readiness
Instead of relying solely on a timer, watch for these signs:
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Start: Yellow-green coating.
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During: Gradually deepening blue-green.
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Ready to rinse: Dark blue with greyish shadows.
5. Test strips – the pro’s method
Just like in darkroom photography, you can expose a strip in timed segments (e.g., cover part every 5 minutes) to find your perfect timing.
Practical starting points
| Light source | Season | Average exposure time |
|---|---|---|
| Full sun | summer | 5–15 min |
| Light cloud | summer/autumn | 15–30 min |
| Overcast | winter | 30–60 min |
| UV lamp/exposure frame | all year | 10–30 min |
Extra tip from Cyanoprints.com
Invest in gloves and an exposure frame to ensure safe, clean, and repeatable results—any time of year.
💙 Conclusion:
Exposure time in cyanotype printing isn’t an exact formula. It’s about balancing light, materials, and your personal style. Start with these guidelines, experiment with test strips, and trust your eyes. With the right tools from Cyanoprints.com, you can capture rich, deep Prussian blues every single time.
