STEP 3:
EXPOSURE TO UV LIGHT
Materials: The Sun is a free source of UV radiation at the cost of control over your exposure environment.
UV light desktop lamp
(Amazon Affiliate link below)
CHOOSING A UV Light Source
Sunlight vs. UV Lamps
Sunlight provides varying UV intensity depending on weather conditions and season. UV lamps or UV bulbs provide a consistent UV output, giving you more precise control over exposure.
SUNPRINT UV INDEX:
KNOW YOUR LIGHT BEFORE YOU START
Printing using sunlight?
The Sun’s UV output changes by the hour, the season, and your location. The same 10-minute exposure that works at noon in July will severely underexpose at noon in October.
Check the Sunprint UV index tool before you print.
Sunprint is a free tool available on The Cyanotype Network. A 7-day UV index forecast for your exact location, plus UVI-to-exposure charts and correction factors.
UV Lamp
Position the negative and medium approximately 10 inches from the light source. This helps prevent overexposure (“blowing out” the image) while still producing a clear result. The ideal distance may vary depending on the strength of the light.
Exposure Time Factors
Exposure time depends on several variables:
The intensity (wattage) of the light source.
The distance between the light and the medium (recommended 9″-11″) .
The desired level of development (depth of burn).
Achieving the right exposure requires balancing these factors, but with consistent lighting and careful adjustments, reliable results can be reproduced. For my lamp I position it ~10″ away for 12-15 minutes.
