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Time-Exposure Sequence (All FL images taken at F2.8, 1 second exposure)
This time-exposure sequence illustrates the darkening of a highly tenebrescent piece of green sodalite (“Chameleon Sodalite”) under natural lighting and fullwave UV (LW + SW). It automatically cycles through a set of 16 images showing the color change under both natural lighting and FW UV.
- 13 images were taken at ten second intervals, starting with a “non-tenebresced” piece.
- Three images were taken at one-minute intervals at the end of the cycle.
- After 5 minutes no appreciable darkening was observed
- The color changes are most significant in the first 30 seconds, and then very gradual for the next 5 minutes.
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Static Images
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Tenebrescent

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Non-Tenebrescent

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Image 3 - Shortwave only. FL photo showing the difference in fluorescense - only under SW - between the tenebrescent and non-tenebrescent states. Due to the quenching caused by the tenebrescense these images were exposed for 16 seconds (see image below for a 6 second exposure).
The shortwave image to the right was taken at F8, 6 seconds when the piece was in a full tenebrescent state - note the very dim FL. In order to show the color change the F-stop had to be opened completely and the time-exposure set to 16 seconds (see Image 3 above).
It appears that the tenebrescense significantly quenches the FL response under SW. Under LW the response is a deep rust as the Image 2 above shows.
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