Uv ?

[Englander]

Hi Guys

Hope you all had a good Christmas ? Santa was kind to me

One of the goodies i got was a UV pen light, when i shone it on my flies i found two or three of my top patterns used tying materials that "Glowed" like neon signs !!

Coincidence ?? Whats the currnet thinking on wether trout can see in "UV"

[shrek]

there are a few theories that trout can see further into the UV spectrum than we do, whether or not they do I can't say, but I do like using UV flies of some sort and seem to have success with them, maybe just a confidence thing, but your find sort of dispells that as you can't be confident of the UV if you didn't know it was in your flies to start with. Until someone asks the trout if they can see UV I guess we'll never know

[ickypimp]

IMO it is nothing more than the emperors new clothes...

UV light has a maximal penetration in PURE water of approximately 7 feet,

During that penetration the inversed square law would apply for every doubling of unit length you 1/4 the intensity.. so from the surface to 3.5 feet down you have already lost 75% of the UV intensity...

Secondly we have to consider the fact that the water we fish isn't pure... as well as containing all kinds of dissolve ionic matter which will further increase the spectral absorption.
The water will also contain a significant quantity of particulate matter, this is where a further physical phenomenon known as Raleigh scattering would become a factor...

Rayleigh scattering - Wikipedia, the free encyclopedia

to cut a long story short the shorter the wavelength (uv is short) the greater the scattering... this would effectively reduce the uv penetration to a neglegable amount...

[bear]

I've got one of those pens.

Loads of flies in my lure box glow, including flies from 10+ years ago.

Now this is the bit I'm not sure about. When people refer to UV flies are they talking about the blue filament ?

The pen highlights what I would refer to as fluorescents, before the UV trend started ?

[ickypimp]

The UV materials people discuss refer to products that are activated by absorbing light in the uv range of the electromagnetic spectrum then use the energy to emit light of a different wavelength somewhere in the visible spectrum

This is where i have issues with the whole concept.... it has been demonstrated many teliosts have the ability to see in the UV , however therse materials are not emitting in the UV they are emitting in the visible... but then it is my reckoning that they will be actually emiting the sum of **** all because of the amount of activating light reaching them...

you are spot on this is fluorescence....

[phaycroft]

Originally Posted by ickypimp

The UV materials people discuss refer to products that are activated by absorbing light in the uv range of the electromagnetic spectrum then use the energy to emit light of a different wavelength somewhere in the visible spectrum

This is where i have issues with the whole concept.... it has been demonstrated many teliosts have the ability to see in the UV , however therse materials are not emitting in the UV they are emitting in the visible... but then it is my reckoning that they will be actually emiting the sum of **** all because of the amount of activating light reaching them...

you are spot on this is fluorescence....

I only use a few wet flies with uV straggle friitz included, when I'm fishing in the surface layer, usually in a bit of a wave and mainly for brownies.

However, I seem to have had more success with the same patterns with the uV material than without for both brownies and rainbows. This is based on returns before I used the uV flies on the same waters as I now use flies with uV material in them.

Do you think this is just a coincidence or is there a possibility that the uV material does have a positive effect when used in or near the surface?

[shrek]

Icky, maybe I am wrong here (wouldn't be the first time lol) but surely the figures you gave are based on how we perceive light (whatever type). Is it possible that trout, or any other species, see light in a different way that us making these figures irrelevant??
And can you not charge UV material before you fish it to give off UV without sunlight?

[arkle]

I've yet to get a copy, but there's a new book that's recently been published on the subject of U.V. & fishes perception of it. "The New Scientific Angling - Trout & Ultra Violet Vision" by Reed F. Curry.

There's a thread where further details of it in Fly Tying in the Classic Streamer & Wet Fly section. The thread makes interesting reading.

[Macmagoo]

I have read something about this and the article made the point that only younger fish can see the UV light.

[Gander]

Originally Posted by Macmagoo

I have read something about this and the article made the point that only younger fish can see the UV light.

I was just thinking the same thing.