7/8/16 Report - Halo Effect, Ground Effects, and Notes On Testing Your Metal Detector. Kirlian Photography.

Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.

Kirlian Photograph of US Half Dollar.
Source: See link belwo.

Yesterday I discussed air tests and ground tests and pointed out one common problem with both of those kinds of tests.  That problem was the say the coil or target was moved.  Today I'll discuss a completely different problem.

If you understand these problems, you'll also have a better understanding of how your detector works, and as a result, be able to use your detector more effectively in the field.

People often bury for ground tests. Some create test gardens.   I'll maintain that very similar results can be obtained by simply laying the target on the ground and then raising the coil above the target.  Little is gained by burying the target.  When the ground is neutral, it can end up being nothing more than a glorified air test.  When the ground isn't neutral, it can end up being worse than an air test for reasons I'll discuss below.

One reason, but not the primary reason, is that the soil is unsettled and loose, but also the object can be standing on end or in some other odd position unless care is taken to position it.  As I've shown in the surface angle of the target is an important factor.  A coin standing on end, for example, will typically give a small and uncharacteristic signal.

When a target is buried for a metal detector test, it is not like the typical target you most likely find during a hunt because during an actual hunt the target has typically been in the ground a while.  As a result there is what is called the "halo effect."

The "halo effect" theory holds that buried metal objects have an ionization "halo" that increases their apparent size to a metal detector searchcoil.  This makes the objects detectable at greater depth.  In other words, according to this theory, long-buried metal objects have something you cannot duplicate with a recently-created test garden.

It takes a while for the halo to form, and the halo effect is greater with objects that have been buried for a longer time.  The halo effect is also increased in certain environments, such as saturated soil.

Here is a web site that discusses the halo effect in detail.

http://www.njminerals.org/metaldetecting-haloeffect.html

Remember also what I've said about compacting sand and soil.

The lack of a halo effect is not the only problem with newly buried targets.  When there is any degree of soil mineralization or conductivity, digging a hole creates discontinuous ground conditions that a metal detector will try to adjust to.  Such disrupted sand or soil will cause your computer to adjust and will often cause false signals, and often a reduction in depth.

It is not unusuaal to detect a coin in black sand, then dig a hole only to find that you can no longer find the target.  In some cases that is due to the difficulty your detecdtor is having in adjusting or interpreting the ground conditions created by the disrupted matrix created when you dug the hole.

OF course different detectors will adjust differently and different settings will also affect how your detector adjusts to those circumstances.

Perhaps the easiest demonstration of this is in black sand at the beach.  The next time you encounter black sand give it a try.  Dig a hole in a concentration of black sand.  You very well might find that you get a signal from that hole.  If you toss a coin into the hole, you might have difficulty detecting it, especially at depth.

It is very much like when a wave comes washes over dry or partially dried sand at the beach.  There will be a line between the newly wet salt sand and the dryer sand.  Sweeping across that line can cause a false signal or a reduction in detecting depth as your detector tries do adjust to the difference.

Regarding the halo effect, here is a summary of three main points from the previously referenced web site.

1.  Test gardens aren't much good unless they are old because the Halo Effect hasn't formed on newly buried objects.  New test gardens are not much better, if any, than an air test.

2.  Noble metals ionize in the ground too.

3.  Some environments create the Halo quicker than others, such as moist and acid environments.

My main point is that not only will the halo effect not be present when a target is newly buried, but there are also other problems, including the fact that the soil matrix has been disrupted.  In some circumstances, that can be a very significant problem.  That will make ground test results different from what you would get from a naturally buried and settled object in the field.

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That reminds me of some Kirlian photography that I used to do.  Kirlian photography allows you to capture an image of elecrical fields around an object, very much like the halo effect.

Here is a little about that.

In 1939 Semyon Kirlian discovered that you could photograph the aura of an object by placing the object on a photographic plate in a high-voltage electric field. The photographic image looks like a colored halo or coronal discharge.

Images created by Kirlian photography were mistakenly thought by some to be a physical manifestation of the spiritual aura or "life force."  What is actually recorded is the result of natural phenomena including pressure, electrical grounding, humidity and temperature. Changes in moisture barometric pressure, and voltage will produce different 'auras'.  So what is actually seen on the photographic plate is gas ionization around the object - living or not.  

Here is a link where you can read more about Kirlian photography and auras.

http://www.skepdic.com/kirlian.html

And here is a link where you can find the photo of the coin shown above plus a variety of other Kirlian photography. 

http://www.bing.com/images/search?q=kirlian+photograph+of+a+coin&id=488C10464835EA7AE5DD735739335BE5CC19D7E3&FORM=IQFRBA#a

And here is the Kirlian photography system that I once assembled in an old brief case.  I did a post about that some time ago.

Kirlian Photography System Assembled in Brief Case

Inside the case (top photo) you see a variable voltage trasnformer and a high frequency induction coil.

On top of the case is a metal electrode plate and a glass dielectric plate.  The glass plate is placed over the electrode plate, then Polaroid film places on top of the glass plate and the object to be photographed placed on top of the Polaroid film.  Then, while in a completely dark room, push the button (white seen through the hole in the case) and the aura is created and picked up by the film.

Unfortunately I can't find any of the old photos I took with this equipment.  I should be able to make some new ones once I warm up this old system.

I intend to get that old system up and running again and take some more photos of coins and other targets.  

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I wanted to express my deep felt sympathies for those who were killed yesterday as well as their families.  It is too bad what has become of our country.

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On he Treasure Coast expect more hot weather and calm surf for days to come.  There is not tropical activity to watch either.   Low tide will be around 5:30 today.   There will be some slightly negative tides.

Happy hunting,
TreasureGuide@comcast.net

9/13/14 Report - Problems With Air Tests. How To Test Your Metal Detector. Buried Objects and Disappearing Signals. Tropical Storm Edouard.

Written by the TreasureGuide for the exclusive use of treasurebeachesreport.BlogSpot.com.

Source: www.nhc.noaa.gov

Not long ago I said the best way to compare detectors is to take the detectors out in the field and compare them on targets that have not yet been dug and compare the signals.  That gives you a comparison in the specific environment.   I'll explain my ideas on testing detectors today and explain some of the problems with some common approaches.

Everybody knows about air tests.  One of the problems that I have with air tests is that the test targets are often not the best.  People tend to use a clad coin of one denomination or another.  As I've explained before, unless you want to find a clad coin, that is not the most relevant test.   Different detectors react to different types of targets differently, therefore you should use test targets that include the types of things you are most interested in finding.  A single test target won't tell the entire story. 

Some people use a nickel because it has a relatively low conductivity, supposedly something like gold, but however true that might be, few gold items are shaped like nickels.   Most gold targets are not solid disks and few are as thick as a nickel.

One big problem with air tests is that they usually aren't done in the type of environment where you will actually use your detector.  They are often done in a house or yard, where there are power lines, underground cables or other sources of electrical interference.  Some detectors react better than others around sources of electrical interference.  That will affect your air test results.  Most beaches are relatively free of electromagnetic interference.

An air test does give you a little information, but it isn't a very good test for comparing detectors or for figuring out how deeply real targets can be detected in the field.

Another approach is to take the detector out and dig a hole and bury a target and then see how deeply the target can be detected.  Of course, for that test to be most accurate, the target should be buried in the type of ground you intend to hunt.   Some detectors will work better in dry ground, others in wet  salt sand, etc. 

Even if you are in the right type of sand or soil, you will not get an extremely good  measure using a newly dug hole.   A target in a newly dug hole will NOT give the same response as a target that has been buried for a good amount of time.

You've probably heard about the "halo effect."  Supposedly a naturally buried object will have a halo effect and therefore give off a stronger signal than a newly buried target.   I won't get into how the halo effect is supposed to work, or even what it is, but I can say that a newly buried target won't give the same signal as a naturally buried target that has been in the ground a while.

Have you ever dug a hole to get a target in the wet salt sand and you couldn't find the target in your scoop or in the hole?   It seemed to disappear.

Here are some things that could have happened.  The object could have slipped down deeper in the hole, or it could now be sticking to the side of the hole and standing on edge, thus presenting less surface area for the detector to detect.  Those are two ways that a target can seem to disappear in a hole, but there is another.

Go to a beach where there is compact wet salt sand.  Dig a hole.  Now run your detector over the hole.  If you are in all-metals mode, you might well get a signal from the hole where you disturbed the sand. 

If you can find some black sand and run your coil over it, you might get some false signals, but if you dig a hole in the black sand, or even disturb the smooth black sand, you'll probably get a bigger signal from that.

If you don't get a signal from the disturbed sand of a new hole or the black sand, your detector is probably canceling that source of noise out and you'll therefore likely be getting less depth.

The thing is, a newly dug hole will change the ground, either causing false signals or changing your ground balance so that your detector is less sensitive.  That is another way an object can get lost in a hole,  The hole itself disturbs the ground, which can cause false signals or a change how your detector is ground balanced.

Another problem with digging a fresh hole in sand, especially wet sand, is that the entire matrix changes.   Just watch a newly dug wet sand hole.  Water will come in and fill it.  Sand and shells will move about and settle,  And if you threw a coin into that hole, you saw where and how it was before you covered it, if that is what you did, but you won't know how or where it settled after that.

Since a target in a newly dug hole will settle, and since a newly dug hole disturbs the sand and creates false signals or changes the detector's ground balance, I do not find newly buried objects a good way to test a detector on a target.   The sand or soil in a newly dug hole is not settled like the sand or soil surrounding a naturally buried object.  And it may have not had time to create a halo effect. 

To me, setting the object on the ground where you intend to detect, and then raising the coil above the object is just as good, or in my opinion, a better way to go.  That way the detector will be responding to the natural undisturbed ground in that area.   It is true that you won't be detecting "through" that type of ground, but if your settings are right, that won't matter much.   I think you will get as good an estimate of depth by raising the coil over an object on the surface as by digging a hole and disturbing the ground. 

Also,if you experiment a little, you'll see that an object in a very well packed area will generally give off a better signal than the same object buried in course material, such as course shell sand.

 

As you can see there are three areas of weather to watch.  (See map at top of post.) The weather system that has been bringing us wind and rain has now moved into the Gulf.

Edouard is still out in the Atlantic, and there is one more disturbance following Edouard.

On the Treasure Coast we still have a small surf and fairly good tides.


Happy hunting,
TreasureGuide@Comcast.net

7/19/13 Report - Ahah!!! How You Might Actually See and Photograph the Halo Effect! Kirlian Photography and Metal Detecting

Kirlian Photograph of US Half Dollar.
Source from link below.

One note before I get started on my main topics today: they discovered some timber on the north end of the Margarita site and are thinking that some of the ship might have gone farther north, so they'll be investigating up that way some more.


I was reading a great article on the Halo Effect as it relates to metal detecting when I experienced one of those moments when you put things together and come up with a totally new realization.  That is supposed to be when you yell Eureka or Ahah!   Anyhow,  I was reading about the halo effect when I realized that I may have actually taken photographs of the Halo Effect many years ago -  long before I became involved in metal detecting.

Below you will see pictures of the Kirlian photography system that I assembled back in the seventies.

You might want to first read this article on the Halo Effect.   It is a very good article on the Halo Effect and how it relates to metal detecting.

http://www.njminerals.org/metaldetecting-haloeffect.html

(Thanks to Robert K. for submitting this link.)


You ask how you can photograph the Halo Effect.  The answer is Kirlian photography. 

In 1939 Semyon Kirlian discovered that you could photograph the aura of an object by placing the object on a photographic plate in a high-voltage electric field. The photographic image looks like a colored halo or coronal discharge.

Images created by Kirlian photography were mistakenly thought by some to be a physical manifestation of the spiritual aura or "life force."  What is actually recorded is the result of natural phenomena including pressure, electrical grounding, humidity and temperature. Changes in moisture barometric pressure, and voltage will produce different 'auras'.  So what is actually seen on the photographic plate is gas ionization around the object - living or not.  


Here is a link where you can read more about Kirlian photography and auras.

http://www.skepdic.com/kirlian.html

And here is a link where you can find the Kirlian photo of the coin shown above plus a variety of other Kirlian photographs of coins and other objects.

http://www.bing.com/images/search?q=kirlian+photograph+of+a+coin&id=488C10464835EA7AE5DD735739335BE5CC19D7E3&FORM=IQFRBA#a

And here is the Kirlian photography system that I once assembled in an old brief case.

Kirlian Photography System Assembled in Brief Case

Inside the case (top photo) you see a variable voltage trasnformer and a high frequency induction coil.

On top of the case is a metal electrode plate and a glass dielectric plate.  The glass plate is placed over the electrode plate, then Polaroid film places on top of the glass plate and the object to be photographed placed on top of the Polaroid film.  Then, while in a completely dark room, push the button (white seen through the hole in the case) and the aura is created and picked up by the film.

Unfortunately I can't find any of the old photos I took with this equipment.  I should be able to make some new ones once I warm up this old system.

I went a little mad scientist on you today, but I got excited when I realized that I might actually be able to take a photograph of the Halo Effect, or at least something very similar.   Not exactly as it would be in the ground, of course.  Still, it is a halo effect and it seems to me that many of the same principles apply. I'll have to think more about how the signal from the detector actually excites the object and the field around it.

That suggests a lot of experiments.  I need a few more life times to get all of that done though.


Here are a few of the main points from the Halo Effect article crudely summarized.

Test gardens aren't much good unless they are old because the Halo Effect hasn't formed on newly buried objects.  New test gardens are not much better, if any, than an air test.

Noble metals ionize in the ground too.

Some environments create the Halo quicker than others, such as moist and acid environments.

I recommend reading the entire article.


On the Treasure Coast this morning, nothing much new in the way of beach conditions.   No wind yet.  The surf is still around 1 or 2 feet.  Expect that to continue for a few days, at least.

There is no organized activity in the tropics to watch.

Low tide today will be about 11:30 AM.


Happy hunting,
TreasureGuide@comcast.net


A need is the first step to a solution.  There are no victories without battles.  In religious terms, a need is the first requirement and ingredient in the making of a miracle.   TG.