CYANOTYPE EXPOSURE ALMANAC
Exposure times are starting points for traditional-formula cyanotype when contact printed in direct sun.
SUNPRINT UV INDEX
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Personalized UVI forecast, anywhere in the world.
UV INDEX – EXPOSURE
| UV INDEX (UVI) | INTENSITY | EXPOSURE |
| 0-1 | N/A | N/A |
| 2 | SOFT | 30-60 MIN |
| 3-5 | MODERATE | 20-45 MIN |
| 6-7 | HIGH | 10-15 MIN |
| 8-10 | VERY HIGH | 6-10 MIN |
| 11-14 | EXTREME | 4-7 MIN |
CORRECTION FACTORS
SOFT EDGES –
Low UVI. Try waiting for a higher UVI to redevelop the print.
Ensure the negative is flat against the developing surface. Even the smallest gap can create diffused light and soft lines.
UNDER-EXPOSURE –
Expose for longer duration.
(Note the time and UVI of the under-developed print and increase the time in brackets. Note that Cyanotype development can take up to 24-48 hours to fully develop the full Prussian blue. washing with hydrogen peroxide can increase the contrast of a underdeveloped print and possibly save it.)
OVER-DEVELOPED –
Seen as intense blues in shadows and highlights with little contrast between.
Expose for shorter period. Again, note the time and UVI of the over-exposed print and decrease the time, or wait for a lower UVI to retry.
UVI 8-14 will start to develop as soon as the UV light meets the cyanotype solution. If unprepared to start the process, this can cause a full page of unintended hue if the negative is not already in place.
STUDIO WETWARE 