Fishing Line Visibility

[Brewcrafter]

This has been addressed before, but this morning I witnessed it and it was striking.  I have a knot tying station on the corner of my workbench/desk in my office garage that i use for practice/stress relief.  And sometimes the cutoffs miss the trash can.  This morning when I went into the garage it literally looked like lava oozing under the door - the photo does not do it justice - the garage is much darker and the garage door is getting the rising sun.  Poor Man's fiber optics!  And in the photo you can even see light is transmitting to where it is reflected in the aluminum trim of the garage door.  For the tech minded this is good old reliable Ande 50# monofilament.  Thanks to Web Guru Shibley for helping post photos that I was too stupid to attach.  Next step, I am going to toss some flouro out there next to it and see what happens...I do realize there were a lot of factors at play here and probably tomorrow morning will be a disappointment but the photo this morning was really cool! - john

[Gobi King]

Aliens trying to look inside you garage and scan for old Penns?

[Brewcrafter]

Ha!  I have some 80# Seguar next to it, we will see what happens in the AM.  Thanks for uploading that photo for me! - john

[philaroman]

if I saw that, my 1st thought: SWAT about to breach & confiscate all the best tackle 

actually, I may be the one who brought up the whole fiber optic thang in older post, which I only read about
never imagined it was so drastic/blatant -- THANKS FOR THE EVIDENCE!!!
I could certainly imagine a shallow sight predator like cuda, ignoring realistic lure & striking the striking leader  

[jurelometer]

We did talk about this awhile back. 

Some of the light that enters the line bounces off the walls instead of just passing through. so you end up with with some photons ricocheting along the line and eventually squirting out the end. The angle that the light enters the line should be a factor.

Since this is an  unclad fiber optic strand, the lower the refractive index of the outer shell and/or the surrounding environment, the more light  gets rerouted. Mebbe the garage door/floor acted as cladding for part of the line, but the rest is affected by the refractive index of the air in contact with the line.

I suspect that when fishing with an unclad strand (mono fishing line)- there will be limited circumstances where this sort of concentration will occur, probably for short stretches very near the surface, mebbe more likely when the line is straight and aligned with the angle of sunlight after it enters the water?

This is a long winded way of saying that you should probably re-execute this experiment with your garage flooded with water

-J

[Sharkb8]

Wow amazing, cool photo

Kim

[Donnyboat]

Very interesting, thanks John Toby, cheers Don.

[alantani]

light saber technology!

[handi2]

It's all gray after 20' of water.

[Brewcrafter]

We did talk about this awhile back. 

Some of the light that enters the line bounces off the walls instead of just passing through. so you end up with with some photons ricocheting along the line and eventually squirting out the end. The angle that the light enters the line should be a factor.

Since this is an  unclad fiber optic strand, the lower the refractive index of the outer shell and/or the surrounding environment, the more light  gets rerouted. Mebbe the garage door/floor acted as cladding for part of the line, but the rest is affected by the refractive index of the air in contact with the line.

I suspect that when fishing with an unclad strand (mono fishing line)- there will be limited circumstances where this sort of concentration will occur, probably for short stretches very near the surface, mebbe more likely when the line is straight and aligned with the angle of sunlight after it enters the water?

This is a long winded way of saying that you should probably re-execute this experiment with your garage flooded with water

-J

I possibly could have accommodated this request for a more "in depth"  test a few weeks prior when the PRV on my water heated failed in the middle of the night and did actually flood the garage.  Yesterday was very overcast, and the morning light was very diffused.  This morning is clear and bright and the two samples I have are equally "glowy" both the 50# Ande nylon and the 80# Seaquar Flouro.  The main conclusion to all this is I need to do a better job sweeping the garage floor and not leaving scraps of line littering the floor! = john

[nelz]

Not sure a dry test is valid, ya gotta consider that the advantage of Flouro is revealed under water. It's supposed to match the refraction of light of the water around it, thus camoflaging it I suppose. Hopefully nylon's not as bad as your sample under the water too.

[Brewcrafter]

Nelz = I totally agree, this was just a happy accident that I found fascinating; as Jurelometer also pointed out, the relevance of all of this is probably nil, at best. - john

[jurelometer]

Science fanboy alert:  I am an enthusiast.  Not trained in this stuff.

Like most of the "scientific" information provided to us by the tackle companies, there is a lot of BS to digest before finding anything nutritious.

I think it works something like this:

First of all a definition: refractive index is  a number that provides the ratio of speed of light through a medium (air, water, beer, fishing line) relative to  a perfect vacuum.  Light travels slightly slower through air than in space, even slower in water, not sure about beer.

When a light wave encounters a transition between mediums at a clean 180 degrees, it just slows down, but continues along its path.

But if it hits at an angle, the light wave will change direction based on the angle and the relative refractive indexes of the two mediums.   This is because one side of the wave will reach the transition plane before the other and will slow down (or speed up) sooner.   This cause  the bent pencil in the glass of water phenomenon that we have all seen.

Now if that medium is in the shape of a cylinder (like a section of fishing line)  weird things start  happening.  Some light will get into the cylinder traveling at an angle. If the combination of angle and refractive index is just right, it will not leave the cylinder. It will just keep bouncing off the walls and travel along the length of the cylinder, along with other similarly trapped light waves.   This circular cross-section is ideal for keeping the light inside.   

With a perfectly straight cylinder, that trapped  light is going to squirt out the end.  But if the cylinder is bent, or the refractive index changes, some or all of that trapped light is going to escape, which is the pulsing light flashing through clear fishing line in shallow clear water phenomenon that has been reported.  I saw a report from an underwater videographer seeing this when filming trout flies tied to fluorocarbon underwater in a stream.

I personally would not lose to much sleep over this for most situations.  I doubt that fishing line makes an efficient  enough fiber optic cable that it would carry bright light from the surface  several yards underwater.  Dunno if a lower refractive index material like  fluoro (vs. nylon)  might increase the odds of  light pulsing in a more perfect scenario.

Regarding visibility, I am skeptical (along with Nelz and others).  While it is true that fluorocarbon lines may have a refractive index closer to water, this does not take into account that  cylindrical boundary, the potential for the line surface to have a different refractive index, the varying refractive index of the surrounding water based on suspended particles, salinity, etc.    The truth is if you stick your head underwater with a dive mask, both nylon and fluoro are very visible to the human eye.  A human with a dive mask will tend to have better visual acuity  than a fish. 

And luckily for us humans, it is unlikely that fish even understand the concept of fishing line . 

My guess is that any fluoro benefit is more specific, useful in limited circumstances, and may not be related to visibility.  I tend not to fish with the stuff unless others are catching with fluoro, and I am not with nylon.  I will also break down and use fluoro if I am going to only get a few shots, and guides/local experts are convinced that fluoro makes a big difference.  Sometimes it is hard to stay the scientific method course

The advent of fluoro has made it more difficult to find that high quality hard/abrasion resistant nylon leader, especially in lighter test sizes. Seems to be mostly a market for fluoro in premium hard leaders nowadays.

-J

[nelz]

Regarding visibility, I am skeptical (along with Nelz and others).

Actually, I'm firmly convinced that fluoro works as claimed because I catch more fish when I use it, and consistently out-catch those around me not using it.

The truth is if you stick your head underwater with a dive mask, both nylon and fluoro are very visible to the human eye.

Have you tried this yourself?

[Maxed Out]

 I'm guessing water clarity has a lot to do with grey scale. Here in the NW we have green water that maybe has 10' of "naked eye" visibility. Blue water would allow more sunlight to deeper water, thus altering the grey scale, but at some point everything loses it's color and is seen as a shade of grey. Some colors disappear at shallower depth than other colors  Red is the first color to blend in with gray scale. It supposedly happens around 30-40' in our brackish green water. Fish have a broader spectrum of ultra violet light that goes well beyond where it turns pitch black to the human eye. There is lot of discussions about the subject on the www

.....edit: it's a deep subject  

-Ted