Do UV Materials Make a Difference?

I imagine no one has failed to see the deluge of UV tying materials. I haven't found UV materials to be any more effective than non-UV materials but was wondering what the experience of others has been.

I recently put a few of my flies under a UV light. Before and after shots are below. What surprised me the most was that generally only materials that were pink or chartreuse were made more visible by the UV light. Other colors became very dark or very washed out. This didn't matter whether the material was marked as UV or not. The hot spots on the flies in the photos were made with UTC 140 Fluorescent Pink and Chartreuse thread. The dubbing collar on the one nymph is made of STS Trilobal Fluorescent Shell Pink. The exception to this was the woven nymph. It is made with rootbeer and orange Jelly Rope, a non-UV material, over silver tinsel.

In an article on Sexyloops, the author touches on the subject of UV light detection in salmonids (http://www.sexyloops.com/articles/whatsalmonidssee.shtml) but leaves the question of whether salmonids can even detect UV light after the smolt stage unanswered.

The thing that I think a lot of people don't realize is that these bright colors aren't necessarily what these materials look like to a fish. For that matter, these bright colors aren't what this material looks like in the UV spectrum either. See...UV radiation is that spectrum of electromagnetic radiation with wavelengths just shorter than that of the visible spectrum (to humans). As such, it has no color (which would, naturally, make it part of the visible spectrum). These glowing, fluorescent images are only a visible-spectrum indicator of UV luminance that happen to use bright colorful light to demonstrate it (maybe because they want to sell a product?).

We CAN measure the amount of UV radiation reflected by objects both with scientific equipment and even high end consumer cameras, but blasting them with a black light and taking a picture is not how it is done. The only thing these pictures show you is how these things MIGHT look to a fish if you drifted them past the fish while shining a black light on them. The appropriate way to photograph UV radiance is to use a filter on a camera that blocks out all electromagnetic radiation with wavelengths longer than UV. This means the filter will look like opaque black glass to the naked eye (because it blocks all visible light). Camera sensors, despite manufacturers best efforts, are slightly sensitive to UV radiation beyond the limits of visible (to humans) light. Using these filters, cameras can capture an image indicative of the amount of UV reflected by given objects. Still, the images recorded are still more of a graph of information than a strict 'photographic image' as it's simply the camera's visual representation of a non-visual quality...and it's in black and white unless given a color overlay.

So long story short, the pretty pictures you see like the ones above are 98% advertising hype. Can fish see into the UV spectrum? I don't know. Maybe. If that CAN, though, nobody TRULY knows what it looks like, but it's likely just a bit of a halo or glow around objects that reflect UV radiation rather than absorb it.

Excuse me for chiming in on the fly forum...I'm not a fly guy, but I do know that the UV and GLOW lures work very well in Ontario for those Kings. Especially while fishing deeper water and in the early morning hours during low light conditions. I agree with COLD, the fish probably do not see the color the way we do, but I do believe they see a brighter image which would show up from farther distances. I bet their lateral lines even pick up the lures' vibrations far before they ever see it, but that brightness/glow has to be an added attraction in my opinion. Pretty neat stuff above though too....I'm sure they attract the fishermen just as much as they do fish, maybe even more.

I fish water that many bait fishermen say is a day away. I am a believer in the UV. In dirty water my uv flies do much better than my non uv flies. Not saying that non uv flies dont catch fish in dirty water. In normal and clear conditions I believe the uv may do better as well. But I have caught many o steel on the Lady Caroline. Swinging flies is a confidence game. I am more confident in my uv flies so that is what I mainly fish. So for obvious reasons my uv flies will catch more than my non uv flies. I am looking for a reaction strike and I believe they react positively. I cannot speak for uv in nymphs or egg flies because a steelhead will get hooked by anything when the line is dredged through thier mouths.