September 2009 Archives

UV Photography Lessons

My first attempt at photographing fluorescent minerals was pretty rough. Although the rocks looked great visually, the camera was less than pleased with the situation. I'm currently using a simple black light to do this, and I quickly realized that the huge amount of visible light produced by these lamps tends to swamp the camera's CCD/CMOS. It really overwhelmed the actual fluorescing colors in my first batch, and I had to do a lot of heavy overall correction in Camera RAW and LAB color space.

After doing some more research, I realized that this is just what professional grade UV lights are made to overcome. They are filtered to emit very little visible light, so that everything you do see and photograph is the result of genuine fluorescence. Because I'm not ready to invest in that kind of set up, I decided to piece together a more affordable system and see how I like it. I purchased a Long Wave UV Filter from UV Systems and paired it with a Phillips black light bulb from Home Depot. By positioning the filter above the rock, then resting the black light over the filter, I got an immediate improvement. Visually the difference was apparent, although not really spectacular. However, the photographs benefited immensely. Notice the comparison below.

The first image is from my original set of photographs using a GE black light bulb and no filter. The second image is from my latest set of photos using the Phillips black light bulb and the Long Wave UV Fillter. These are original, unprocessed images, opened using the default Camera RAW settings, with only scaling, cropping and labeling applied.

Original photo using GE UV bulb and no filter

Latest photo using Phillips UV bulb and Long Wave UV filter

I've replaced the images in that original post with the new photos, including a new angle of the rock to show a striking sliver of white running across one side.

I had basically given up on a piece of fluorescent chalcedony from that original photo session that glowed with a soft orange. The purple overwhelmed it and I couldn't get rid of it without eliminating the fluorescent orange too. Using the new bulb and filter I got excellent results with it last week. So I'll eventually get that one posted here too.