Application: Practical Searching with Fluorescence

Fluorescence is good for more than science and finding beauty in nature. It can also be put to many practical uses.

I was traveling recently, and as I was preparing to take a vitamin D capsule I dropped it on the hotel room floor. The capsule is about .9 cm (3/8″) long and is almost transparent, with a slight brownish tinge. The photos below show a close-up of a capsule and a section of the carpet I dropped it onto. There was no sound, and it could have bounced and rolled over a considerable area.

(Click on any image for larger version)

I looked around for a minute without success. I like finding things, and I like a challenge. Then I thought – “What if the capsule fluoresces?” I often happen to have the tools at hand to answer that question, so I took out my Light & Motion GoBe light with the NIGHTSEA head and a pair of the NIGHTSEA yellow filter glasses. The first thing I did was check if the pills fluoresced. They did, as you can see in the photo below.

Then I scanned the floor with the light and glasses, not bothering to try to make the room dark. I found the pill almost immediately. The photos below show the section of floor in white light and with fluorescence added. The first picture was taken with ambient room light, and to get the second image I kept the exposure settings the same but added the yellow barrier filter and added illumination from a blue light flash.

The next pictures show the pill on the floor in greater detail. This time for the fluorescence shot I shortened the exposure to eliminate the ambient light and isolate the fluorescence.

Fluorescence to the rescue! Lots of things around us fluoresce, and sometimes you can take advantage of that even for mundane but useful tasks. And sometimes for more important tasks.