FMS - The Fluorescent Mineral Society

High Dynamic Range image stack

This test photo was taken with a 5 megapixel Minolta Dimage 7i digital camera. To get the extreme dynamic range, it is actually four different exposures "stacked" using my own HDR algorithm. For more info on the process, Google for HDR (high dynamic range) and Image Stacking algorithms.

That Minolta camera is well suited for fluorescent mineral photography, with excellent color rendition, 30 second exposures limit, and the ability to preview manual focus in near darkness. Nikon Coolpix cameras have problems with deep blues turning to magenta, and some Canon cameras intentionally desaturate red colors to orange/pink (apparently better for shooting rock concerts).

The background is black lycra cloth. It is flat black, stretchable, and doesn't attract dust like velvety fabrics.

The minerals, clockwise from the left, are:

Fluorite cube shard - $2 at a rockshop.
Desert rose - chalcedony with uranyl activator, collected on a hill East of Oatman, AZ.
Terlingua type calcite shard - $1 at a Tucson gem show booth.
Willemite on calcites - collected from mine tailings used for railbed - Ogdensberg, NJ.
Fluorite on Calcite - Castle Dome, AZ - 1$ find in a box of misc at a local mineral show.

The SW light source is a used 80watt medical gel fluorescece transilluminator from the left, with a mylar reflector off to the right. (A weaker lamp would do, and it would look better lit from above).

Some dust motes were removed with photoshop. The very brightest willemite green spots are not blown out, but compressed to increase the contast of the overall image. The black level could be clipped for even more contrast, but I wanted to show the noise-free depth of the capture.

The calcite really does fluoresce in orange and red, with an odd patch that lights up orange in MW UV and blue light. The patch also phosphoresces strongly.

Note that enough shadow detail was captured that the minerals appear illuminated by their neighbors.

Enjoy,
Ed Anderson - FMS webmaster