UV or not UV that is the question!

11foot5

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Pardon the simplicity of my approach here, but I don’t understand this UV material thing! If the human eye can’t see UV, how do we know that it’s present in materials? My (very limited!) understanding is that the materials which “glow” when a UV torch is shone on them is just fluorescence.....can anybody explain in layman’s terms??!!
 

Cap'n Fishy

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Pardon the simplicity of my approach here, but I don’t understand this UV material thing! If the human eye can’t see UV, how do we know that it’s present in materials? My (very limited!) understanding is that the materials which “glow” when a UV torch is shone on them is just fluorescence.....can anybody explain in layman’s terms??!!
My take on it...

Yep - we have visited this before a few times. Consensus is that anything called 'UV' is The 'Emperor's New Clothes', designed to get you to buy it. Lots of things reflect UV light to different degrees, none of which our eyes can detect, and so we are powerless to know whether what is being sold us has any special properties. It seems a distinct possibility the whole fad is based round it having a nice purplish translucence, which got it the name 'UV'.

Daylight fluorescence is very much a real thing and very much something to take seriously. UV light is changed in wavelength (when being reflected) into the visible spectrum, and our eyes (and we assume those of fish) then see it as the extra glow.

Extra UV reflectivity may or may not be useful in fly-tying (no one seems certain on that one!), but without an expensive UV detector to sort the wheat from the chaff, we may as well forget about it. We have no way of knowing when we are being sold a pig in a poke.

Col
 

11foot5

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My take on it...

Yep - we have visited this before a few times. Consensus is that anything called 'UV' is The 'Emperor's New Clothes', designed to get you to buy it. Lots of things reflect UV light to different degrees, none of which our eyes can detect, and so we are powerless to know whether what is being sold us has any special properties. It seems a distinct possibility the whole fad is based round it having a nice purplish translucence, which got it the name 'UV'.

Daylight fluorescence is very much a real thing and very much something to take seriously. UV light is changed in wavelength (when being reflected) into the visible spectrum, and our eyes (and we assume those of fish) then see it as the extra glow.

Extra UV reflectivity may or may not be useful in fly-tying (no one seems certain on that one!), but without an expensive UV detector to sort the wheat from the chaff, we may as well forget about it. We have no way of knowing when we are being sold a pig in a poke.

Col
Thanks for that Capt! That was my gut feeling too! I think that fluorescence is “real” we can experience that easily, but UV is hard to experience if at all possible, I don’t know. Put it in your flies and test the results I guess. Fifty years ago my dad bought me the book “The truth about fluorescence” by Thomas Clegg and a set of DRF materials (floss and wool?). I wish I had it now! As a very young tier and fly fisher, I did think fire orange was the most effective.....seems to me it’s the colour still used the most consistently with red a close second?
 
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Iberian

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Pardon the simplicity of my approach here, but I don’t understand this UV material thing! If the human eye can’t see UV, how do we know that it’s present in materials? My (very limited!) understanding is that the materials which “glow” when a UV torch is shone on them is just fluorescence.....can anybody explain in layman’s terms??!!
The material absorbs uv light (which is invisible to the naked eye) and then re-emits it as visible light, this is the basis for fluoresence. This occurrs to some degree in natural daylight because of the uv component from sunlight. The effect of fluoresence is to increase the brightness of a given material (think of it as a kind of built-in backlighting). Now, whether this makes a fly tied with this material more attractive to fish, I have no idea!
 

Cap'n Fishy

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The material absorbs uv light (which is invisible to the naked eye) and then re-emits it as visible light, this is the basis for fluoresence. This occurrs to some degree in natural daylight because of the uv component from sunlight. The effect of fluoresence is to increase the brightness of a given material (think of it as a kind of built-in backlighting). Now, whether this makes a fly tied with this material more attractive to fish, I have no idea!
You are describing daylight fluorescence, which we know about and which is a totally different thing from the subject of "UV reflection". The OP is asking about materials described as "UV" (UV reflecting), not materials described as fluorescent.

This sort of nonsense...

 

wobbly face

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Trout don't talk or wright so we can't communicate with them. However, from scientific research, people who have studied trout sight and biology of trout's eyes do think they can see part of the UV spectrum (only a part) but this diminishes as the trout age.
What we see (and probably the trout) is the violet range of the colour spectrum. When we use a UV light source (as with UV resin) we only see the violet colour in the spectrum, we cannot see Ultra Violet.
So in Cols pic, all we see is violet being reflected back as all other colour is absorbed by the material, same with the silver, we see silver being reflected back. No Ultra (U) is seen because we cannot see it, nor can the old trout.
 

Cap'n Fishy

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Aye, it's bad enough that folk obsess with UV this and UV that, as if it's some kind of wonder material that bestows their flies with extra fish-catching properties because it's "UV". They could be getting sold any old thing that the maker has chosen to print "UV" on the packet just because it has a purple sheen. But even if it did have some additional UV reflecting properties, it seems unlikely that the fish will detect it. And even if they did, whether it would make the fly any more attractive than any other material is impossible for us to work out when we have no input on any of it - we can't see UV, we can't detect UV reflectivity, or measure UV without highly specialist equipment. We can't tell apart which materials (if any) are kosher from which are just a con. All we can do is use the materials and if the flies we are tying work, then keep using them.

Col
 

silver creek

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The interest in UV tying materials really peaked with Reed Curry's publication of his book "The New Scientific Angling Trout and UV Vision."


Here is Reed Curry's Midcurrent article about trying to match UV for trout fishing.


Here is Simon Blanford's Midcurrent article about trying to match UV for trout fishing.


I personally have had many back and forth posts with Reed regarding whether UV REFLECTIVE tying materials are practical to imitate the UV reflectance of the food items that trout eat.

There are multiple issues with trying to imitate what naturals food items loole like to trout under UV light.

1. Young trout, parr, have a UV chromophobe. They have specific 4th cone that sees into the UV presumably to locate food items that young trout eat. But this cones disappears as the trout matures out of the parr state.

2. Trout also have a blue cone like humans BUT this cone. Cone activity is centered a specific wavelength BUT the "see" and are activated over a spectrum. The trout's blue cone "sees" and is activated by the higher wavelengths of UV light so they "see" more deeply into the UV spectrum than we humans can. Actually we humans see below 400 NM so we see the higher UV light as well.

HOWEVER, and here is a big however. Because the cone is a BLUE cone the UV light that activates the BLUE cone is PERCEIVED as the color BLUE. The trout and we CANNOT distinguish how much of the activation of the blue cone is by blue light, UV light or bluish light. The trout sees this trace UV reflection as the color blue.

3. Since humans cannot see the UV reflectance of the naturals or the UV reflectance of fly tying materials, there is no practical way to choose fly tying material to match the UV reflectance of the naturals so as anglers. This should be self evident.

Consider a person who has Red/Green color blindness. This is what apples look like.



We are "color blind" to UV colors. Therefore, EVEN IF trout could see "UV colors", we cannot and therefore, trying to match UV colors is a fools game.

Here are two conversations between Reed and I on the NAFF. Reed Curry posts as "overmywaders"



Here is one from the Flytyingforum. Reed Curry posts as "overmywaders"


I have written about UV and trout vision on other fishing sites including the NAFF. I start on this page part way down in response to a question on UV on an earlier page.

 

Cap'n Fishy

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We are "color blind" to UV colors.
It's not quite the same as being 'colour blind'. People with red-green colour blindness detect and process wavelengths of red and green light, but can't properly separate them and assign red and green to them in their brains. They still see colours, and they see the red and green apples - so 'blindness' is an inaccurate term to call it. 'Colour confusion' would be a better term. None of us can detect or process light in the UV part of the spectrum that is supposedly the range that UV materials are reflecting. If the only light present is UV, then we will be in the dark and will be blind.

Yer man Ovemywaders was on a thread on this forum on the subject of UV a few years ago. I tried to reason with him on how it's totally pointless us trying to do anything about it in the absence of specialist equipment, but he wasn't having it. I'm afraid he made very little sense to me.

Col
 

Jeltz

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It's a marketing ploy IMO, the idea that you catch more fish by using UV materials in lures is pure guess work. The fact is, you can catch fish on any type of lure, so to use UV or not makes no difference to me.
 

Shangerlad

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Thanks for that Capt! That was my gut feeling too! I think that fluorescence is “real” we can experience that easily, but UV is hard to experience if at all possible, I don’t know. Put it in your flies and test the results I guess. Fifty years ago my dad bought me the book “The truth about fluorescence” by Thomas Clegg and a set of DRF materials (floss and wool?). I wish I had it now! As a very young tier and fly fisher, I did think fire orange was the most effective.....seems to me it’s the colour still used the most consistently with red a close second?
If you still fancy the book,google it, available second hand from £12.
 

Cap'n Fishy

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I did think fire orange was the most effective.....seems to me it’s the colour still used the most consistently with red a close second?
I've been using fluorescent materials in my flies since the materials widely appeared in the 1970s. Used to get the DRF materials from Tom Saville. I mostly use orange, red, yellow, green, Orkney Peach (mix of Globrite 7 and 8) (or arc chrome), sunburst and don't forget white - there is a vast difference in brightness between fluorescent white marabou and non-fluorescent white marabou. ;)

The WOIGO deer hair I use for my Kate muddlers is fluorescent too. Here it is under UV light...



😜

Col
 

billy fish

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Thanks for that Capt! That was my gut feeling too! I think that fluorescence is “real” we can experience that easily, but UV is hard to experience if at all possible, I don’t know. Put it in your flies and test the results I guess. Fifty years ago my dad bought me the book “The truth about fluorescence” by Thomas Clegg and a set of DRF materials (floss and wool?). I wish I had it now! As a very young tier and fly fisher, I did think fire orange was the most effective.....seems to me it’s the colour still used the most consistently with red a close second?
 

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ejw

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Have used UV for years, found that some supposed UV materials just didn't work ? Now I take a UV torch to check - If it doesn't "Glow" then I don't use it. Red, green and white seem best and the better ones will really glow under a uv light, just don't use too much.
 

Cap'n Fishy

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Have used UV for years, found that some supposed UV materials just didn't work ? Now I take a UV torch to check - If it doesn't "Glow" then I don't use it. Red, green and white seem best and the better ones will really glow under a uv light, just don't use too much.
You are talking about daylight fluorescence, not UV reflectivity.

If it glows under a UV torch, you are seeing fluorescence, not UV reflectivity. Our eyes do not detect UV reflectivity, whether under a torch or by any other means.

Col
 

11foot5

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Thanks gents for all the posts , it’s an interesting subject. Billy fish, thanks for the picture of the book, I haven’t seen that in maybe the best part of fifty years!!!
 

ejw

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Col
Thanks for the info, I was aware, but have found that the fluorescence bit works in my flies.
Billy Wainwright used to do an excellent talk this subject, along with the difference between the two. if you go to the "next" level, phosphorescence may be a step too bright.
White marabou especially from Veniards has UV/ fluorescence due to the washing process. Others can be treated to "Glow" by washing in "miracle glo" or similar "whitening" washing products.
The reason I use the UV torch is if you do it on a Jungle Cock cape or feather it will glow. Now either that proves it has been through a "washing process" or it is a natural glow. So if it works on JC and they have been used for a long time to add a "hot spot" then I will try to copy with other products that glow. Trouble being so many manufactures claim UV qualities that may or may not be true, but in my case I will stick to the "if it glow's" method, fish like it.
 

Wee Jimmy

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Col
Thanks for the info, I was aware, but have found that the fluorescence bit works in my flies.
Billy Wainwright used to do an excellent talk this subject, along with the difference between the two. if you go to the "next" level, phosphorescence may be a step too bright.
White marabou especially from Veniards has UV/ fluorescence due to the washing process. Others can be treated to "Glow" by washing in "miracle glo" or similar "whitening" washing products.
The reason I use the UV torch is if you do it on a Jungle Cock cape or feather it will glow. Now either that proves it has been through a "washing process" or it is a natural glow. So if it works on JC and they have been used for a long time to add a "hot spot" then I will try to copy with other products that glow. Trouble being so many manufactures claim UV qualities that may or may not be true, but in my case I will stick to the "if it glow's" method, fish like it.
You missed the point ejw, the human eye can’t see in the ultra violet.The “glow” you are seeing is fluorescence.

BTW...The whole uv reference in fly tying materials is all about the purple /violet coloured translucent strands within it.Misleading marketing,nothing “ultra”about it.
 

Cap'n Fishy

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Col
Thanks for the info, I was aware, but have found that the fluorescence bit works in my flies.
Billy Wainwright used to do an excellent talk this subject, along with the difference between the two. if you go to the "next" level, phosphorescence may be a step too bright.
White marabou especially from Veniards has UV/ fluorescence due to the washing process. Others can be treated to "Glow" by washing in "miracle glo" or similar "whitening" washing products.
The reason I use the UV torch is if you do it on a Jungle Cock cape or feather it will glow. Now either that proves it has been through a "washing process" or it is a natural glow. So if it works on JC and they have been used for a long time to add a "hot spot" then I will try to copy with other products that glow. Trouble being so many manufactures claim UV qualities that may or may not be true, but in my case I will stick to the "if it glow's" method, fish like it.
As Jimmy says, the best way to avoid confusion is not to use the term 'UV' at all. It is not required. Just use the term fluorescent, or 'daylight fluorescence'. The materials that glow are glowing fluorescence. Yes, the source of that is UV light, but all the materials sold with "UV" this or that marketing nonsense on them are not fluorescent and do not glow (unless they are also fluorescent in addition to all the "UV" marketing nonsense).

Col
 
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Cap'n Fishy

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Fifty years ago my dad bought me the book “The truth about fluorescence” by Thomas Clegg and a set of DRF materials (floss and wool?). I wish I had it now!
With Billy Fish posting a photo of the cover of that book, it gradually... slowly... rang a bell in the deepest recesses of my grey matter. After many hours, I thought: "I definitely recognise that cover." "If fact, do I not have that wee book?" I had a search along my book shelves and... Bingo! Found it! It must be over 40 years since I last read it. I'll have a wee read of it today! (y)

Col
 
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