Quiz: Why is COLOR important for authentication? 1 1

[Insider]

3 hours ago, RWB said:

Multiple factors affect lighting for close examination (and photography). In summary these are: incident background, ambient lighting, source spectrum, intensity, source scale ratio, angle of incidence.

Incident background  -  This is the color and brightness of the area within your field of view behind the coin being examined. This should be 18% reflectance neutral gray. A 90% white background can be used if it is not too close to the coin.

Ambient lighting – General lighting in the examination room. Preferably indirect, low intensity sufficient for taking notes but not competing in brightness with the examination light. No ceiling fluorescent, vapor or other lights.

Spectrum – 5500K daylight, nearly flat energy curve. Modern “white” and adjustable LEDs are preferred.

Intensity -  Approximately 1,700 lumens. (This is the radiant flux after allowance for human vision system.)

Source scale ratio – This is commonly approximated as the ratio between source diameter and a standard working distance of 500mm between coin and light. A 10mm LED source at 500mm distance has a ratio of 0.02; if the light source is 20mm the ratio would be 0.04. As the ratio increases the source becomes broader and more diffuse, eventually resulting in wiping out of most detail. Laboratory preference in artifact examination and restoration is a ratio of 0.02 to 0.08. For coins, I prefer 0.04 as a compromise of contrast and shadow detail. (Known as angular size in more precise circumstances.)

Angle of incidence – Variable as coin is tilted and rotated to better discern surface.

The type, color and size of reflector holding the light source is also a factor and will somewhat alter the effects of lighting...generally making it "softer" and "warmer."

 

So, with regard to those 6 factors, what would be the ideal combo in a coin grading situation?  I have heard that sunlight is good.

[Insider]

1 hour ago, RWB said:

Among the best LED light arrays for document copy work at these:

 

 

 

 

SpectroLED Essential Bi-Color LED and Daylight LED lights. Bi-Color have color temperatures of 3200K and 5600K; daylight has only 5600K. Very low heat, and stable color over life of LED. Very low power drain but allows copy exposures of f-16 at 1/125-sec ISO 200. Look for similar specifications for 2- and 4-LED arrays for coin examination.

 

 

What is document copy work?  Xerox?

[VKurtB]

11 minutes ago, Insider said:

What you don't seem to understand YET is that a person using TWO EYES - the normal way we see things, a stereo microscope set at 7X, and florescent light ("No defect can Hide from florescent light" a quote from the makers of three million dollar automobiles) can see EVERYTHING there is to see on a coin.   Furthermore, I'll guarantee that I have looked at more coins more closely in my short career than either of the two respected numismatists you mention.   Therefore, I respectfully disagree with both of them. 

Furthermore, while you don't count at all because you have never looked at a coin using a stereo microscope and florescent light, I do value your "parroting" defense of the status quo through the experiences of OTHERS!!

I believe standards matter, while reminding you that even the 7th edition of the “Official American Numismatic blah blah blah” endorses modern commercial grading as practiced by PCGS and NGC. There are differences from the 1st to 7th editions, and the 8th or 9th may need to include new lighting standards. I hope it does, because I do not see our “betters” (as if...) allowing us access to bright incandescents much longer.

Edited September 7, 2020 by VKurtB

[VKurtB]

1 minute ago, Insider said:

What is document copy work?  Xerox?

Until and unless xerography attains color fidelity comparable with silver halide photography, which it has not yet done, it means whatever type of color photography gets you closest to the original in “look”. “Feel” is the stuff of Star Trek replicators. Special purpose sheet films are still used for the ultimate in document (even oil paintings) copy work.

[VKurtB]

10 minutes ago, Insider said:

So, with regard to those 6 factors, what would be the ideal combo in a coin grading situation?  I have heard that sunlight is good.

Sunlight has an unfortunate problem - getting it to precisely where it is needed. It has portability issues.

[RWB]

4 hours ago, Insider said:

See if this reply makes sense to you:  I don't know anything about microwave ovens.  Nothing about wattage, microwaves, or how they work.  I have heard that the microwaves agitate something inside of things.  I once read they were used to make our diplomats sick.  However, I do know how to set the timer (even the clock) on the microwave oven in my kitchen and the results are outstanding.  Therefore, I don't need to know the answer to any of your questions about florescent light.  However, I am anxious to learn something from you.  

Sorry, but your reply avoids saying anything about the fluorescent lights you use - and fluorescent lights have nothing to do with microwaves except being part of the broader electromagnet spectrum. Permit me to rephrase the request:

Are they long tubes, or tightly coiled, or something else?

What is the wattage (printed on the tube)?

Manufacturer (printed on the tube)?

How do you orient the light to the coin and to yourself -- that is, does the light face you with her coin in between, or is it behind you (such as over you shoulder) lighting the coin, or possibly to one side?

How far do you recommend putting the light from the coin?

What, in your opinion, makes this light superior for examining coins/medals?

Edited September 8, 2020 by RWB

[Henri Charriere]

Nobody's broached this, the hour is late (at least on the east coast) let me give this a try...

Your chronological age more than anything else will dictate whether you prefer incandescents over fluorescents irrespective of wattage, manufacturers, positioning, angles or anything else, with the older collectors being partial to the former and the younger to the latter. That's it in a nutshell.  Good nite to all, and to all a good nite!

 

[Insider]

32 minutes ago, RWB said:

Sorry, but your reply avoids saying anything about the fluorescent lights you use - and fluorescent lights have nothing to do with microwaves except being part of the broader electromagnet spectrum. Permit me to rephrase the request:

Are they long tubes, or tightly coiled, or something else?

What is the wattage (printed on the tube)?

Manufacturer (printed on the tube)?

How do you orient the light to the coin and to yourself -- that is, does the light face you with her coin in between, or is it behind you (such as over you shoulder) lighting the coin, or possibly to one side?

How far do you recommend putting the light from the coin?

What, in your opinion, makes this light superior for examining coins/medals?

Permit me to rephrase the request:  Sorry, I thought you were being your typical... I shall look tomorrow.  For now:

Are they long tubes, or tightly coiled, or something else?  Long double tube jewelers bench lamp. 

What is the wattage (printed on the tube)?  ?

Manufacturer (printed on the tube)?  GE if I remember.

How do you orient the light to the coin and to yourself -- that is, does the light face you with her coin in between, or is it behind you (such as over you shoulder) lighting the coin, or possibly to one side?  Directly as possible over the coin. 

How far do you recommend putting the light from the coin?  While under the scope it is aprox. six inches.

What, in your opinion, makes this light superior for examining coins/medals? 

This is NOT my "opinion."  It is an observable FACT!  It eliminates all reflection from the coin's surface so anything on or into it is visible when the coin is in the right orientation to see it.  You can crank the power up to 80X using any type of light and not see something if the coin is not in the "right" orientation.  That's why we recommend folks learn to tip and rotate a coin at the same time while viewing it. 

 

Edited September 8, 2020 by Insider

[Cat Bath]

Should I be cautious when trusting my self-illuminated pocket magnifier at shows?

[RWB]

Well, that's a little better. Maybe it's possible to figure out how your claim can be validated. And, it is your "opinion" without facts or at the least very clear anecdotal information. Has your method ever been compared, side-by-side, with others by equally experienced people?

[Henri Charriere]

7 hours ago, Cat Bath said:

Should I be cautious when trusting my self-illuminated pocket magnifier at shows?

To paraphrase a former defense secretary, Just as I must go to war with the press coverage I get, whether it's the press coverage I want or may not wish to have, you, Cat  Bath, the humble collector well received by all, must do with going to shows with the portable lighting you have, whether it's the source of illumination you might wish to have or not. Short term intermittent use is fine; these gentlemen are talking long term, in for the duration, professional grading use, I believe.

[VKurtB]

7 hours ago, Cat Bath said:

Should I be cautious when trusting my self-illuminated pocket magnifier at shows?

Your magnifier light is fine for coin “screening” or “thinning the herd”. But if you want the best way to emulate what the graders saw, or will see, in the circumstance of a raw coin, it’s perfectly okay to use one of the dealer’s incandescent table lamps to get down to the serious choices. It’s kind of what they are there for. For ANA shows, Sam Joseph of the ANA conventions staff spends a fair amount of his “between shows” time trying to source more 100 watt incandescent bulbs for the bourse. It’s getting difficult.

Edited September 8, 2020 by VKurtB

[Henri Charriere]

16 minutes ago, VKurtB said:

it’s perfectly okay to use one of the dealer’s incandescent table lamps to get down to the serious choices.

Just curious, having never attended a coin show myself, but having spent some time in New York's Diamond District before the advent of fluorescents when goose-necked light-bulb lamps is all I remember, how does lighting on the convention floors break down?  More of one over the other, about even, or difficult to tell? 

[VKurtB]

26 minutes ago, Quintus Arrius said:

Just curious, having never attended a coin show myself, but having spent some time in New York's Diamond District before the advent of fluorescents when goose-necked light-bulb lamps is all I remember, how does lighting on the convention floors break down?  More of one over the other, about even, or difficult to tell? 

The convention supplies simple “panagram” style fixtures with 100 watt bulbs. Some dealers bring their own lighting with them. One of the ongoing maintenance tasks at “convention services” is replacing the 100 watt bulbs. The show also supplies the fixtures and bulbs in the auction lot viewing room, where registered bidders examine even seven, and very occasionally, eight-figure coins with those very same panagram fixtures and 100 watt incandescent bulbs.

 

Good enough for them, but apparently not for Skip. I dunno. You tell me.

Edited September 8, 2020 by VKurtB

[Henri Charriere]

23 minutes ago, VKurtB said:

The convention supplies simple “panagram” style fixtures with 100 watt bulbs. Some dealers bring their own lighting with them. One of the ongoing maintenance tasks at “convention services” is replacing the 100 watt bulbs. The show also supplies the fixtures and bulbs in the auction lot viewing room, where registered bidders examine even seven, and very occasionally, eight-figure coins with those very same panagram fixtures and 100 watt incandescent bulbs.

 

Good enough for them, but apparently not for Skip. I dunno. You tell me.

Can't. I'm gobsmacked.

[VKurtB]

10 hours ago, RWB said:

Are they long tubes, or tightly coiled, or something else?

If they are what I think they are, they are like this:

 

 

Either way, I’m still not a fan.

Edited September 8, 2020 by VKurtB

[RWB]

2 hours ago, VKurtB said:

If they are what I think they are, they are like this:

Either way, I’m still not a fan.

What I'm attempting to do is understand Skip's equipment and methodology. He places a great deal of value in the results and I want to understand how the process compares with others, and more important, identify aspects that might show us all how and why his approach is superior. That is, I'm not looking for judgements or decisions, but for the information necessary to objectively evaluate Skip's process.

[VKurtB]

5 minutes ago, RWB said:

What I'm attempting to do is understand Skip's equipment and methodology. He places a great deal of value in the results and I want to understand how the process compares with others, and more important, identify aspects that might show us all how and why his approach is superior. That is, I'm not looking for judgements or decisions, but for the information necessary to objectively evaluate Skip's process.

Damned fine of you, sir. I am similarly curious, but I start form a point of extreme skepticism, as I do in all things. "Extraordinary claims require extraordinary evidence."

 

I have a hypothesis brewing in my mind. I wonder if Skip has ever used LED arrays under his stereo microscope, and if he has, what he thinks about them. I am of mixed feelings about them. Not as compelling as I had hoped.

Edited September 8, 2020 by VKurtB

[RWB]

8 minutes ago, VKurtB said:

Damned fine of you, sir. I am similarly curious, but I start form a point of extreme skepticism, as I do in all things. "Extraordinary claims require extraordinary evidence."

I have a hypothesis brewing in my mind. I wonder if Skip has ever used LED arrays under his stereo microscope, and if he has, what he thinks about them. I am of mixed feelings about them. Not as compelling as I had hoped.

I, too, have some thoughts, but I want to understand what Skip does first.

[VKurtB]

7 minutes ago, RWB said:

I, too, have some thoughts, but I want to understand what Skip does first.

I don't always get to the same point you're going, Roger, but I do have to admire your method. For now, I'm satisfied to wait to see if the lamp I pictured is essentially the correct type, and then take the next step. The shape does matter, even if not everybody gets that.

Edited September 8, 2020 by VKurtB

[RWB]

It's simply the old scientific method with a different starting point. The result is always better knowledge even if the hypothesis is not supported.

[VKurtB]

If at the end of this process, my stereo microscope turns out to be festooned with LED's, incandescents, and fluorescents, each for a different purpose, I'm okay with that. 

I do have to admit to both you, and Skip, and even everybody else here, that the "I know how to flush a toilet" and the "I know how to heat food in a microwave" defense just grates on my last nerve. That I'm able to not smash the screen when I read that is a monument to good blood pressure drugs.

Edited September 8, 2020 by VKurtB

[Insider]

12 hours ago, Cat Bath said:

Should I be cautious when trusting my self-illuminated pocket magnifier at shows?

These are OK.  Most important is to choose one system/magnifier/light and don't switch around.  This is impossible at shows.   Your eye gets accustomed to the color of a coin under a specific light.  When I use my OTT florescent light at shows, everything looks different.

[Insider]

11 hours ago, RWB said:

Well, that's a little better. Maybe it's possible to figure out how your claim can be validated. And, it is your "opinion" without facts or at the least very clear anecdotal information. Has your method ever been compared, side-by-side, with others by equally experienced people?

GE SP35 bulb.  More important is to choose one system/magnifier/light and don't switch around.  This is impossible at shows.   Your eye gets accustomed to the color of a coin under a specific light.  When I use my OTT florescent light at shows, everything looks different.

Roger, I have nothing to prove.  If it is good enough for the US mint to use when examining coins and dies, that's good enough for me.  When it is good enough for the watchmaker schools, it's good enough for me.  If it makes it extremely easy for anyone to see the first signs that a coin may not be Mint State, that's good enough for perfectionists' who don't collect "almost."    

Anyone can test this for themselves.   

[RWB]

4 minutes ago, Insider said:

GE SP35 bulb.  More important is to choose one system/magnifier/light and don't switch around.  This is impossible at shows.   Your eye gets accustomed to the color of a coin under a specific light.  When I use my OTT florescent light at shows, everything looks different.

Roger, I have nothing to prove.  If it is good enough for the US mint to use when examining coins and dies, that's good enough for me.  When it is good enough for the watchmaker schools, it's good enough for me.  If it makes it extremely easy for anyone to see the first signs that a coin may not be Mint State, that's good enough for perfectionists' who don't collect "almost."    

Anyone can test this for themselves.   

OK. When do you use your fluorescent light?

Are observations visual, with hand magnification, with a stereo microscope at 10x to 60x or some combination?

What, specifically, do you detect with it. Is the OTT fluorescent a different shape than the folded tube you mentioned?

How have you compared this to other light sources or methods?

[Insider]

4 hours ago, VKurtB said:

The convention supplies simple “panagram” style fixtures with 100 watt bulbs. Some dealers bring their own lighting with them. One of the ongoing maintenance tasks at “convention services” is replacing the 100 watt bulbs. The show also supplies the fixtures and bulbs in the auction lot viewing room, where registered bidders examine even seven, and very occasionally, eight-figure coins with those very same panagram fixtures and 100 watt incandescent bulbs.

 

Good enough for them, but apparently not for Skip. I dunno. You tell me.

Apparently, this explanation was not posted in this thread.  I have ALWAYS had two lights on my desk.  A large 2 bulb florescent jewelers bench lamp with a cut out to shove a stereo scope into the shade.  A coin lamp as seen at shows and grading rooms with a 100W incandescent light bulb.  With most coins, I take the coin out of its flip and look at it under the light bulb, then I look at it using a 7X hand lens.  Next it goes under the zoom scope at 7X and I use florescent light.  Then I look at it under the incandescent AGAIN with my unaided (nearsighted) eyes.  All the while the little computer in my head has been taking notes and weighing what I've been seeing.  I see things under the scope (Remember that nothing can hide from florescent light if you tip and rotate the coin) that are detracting but MANY DON'T MATTER because you won't see them FOR SURE!   However, I alert the next grader and finalizer about what I saw in my notes.  Me, my company and every TPGS straight grades coins I wouldn't give away as a free gift.  It is called "commercial grading."  

I teach students to see EVERYTHING there is to see on a coin so that they can make an INFORMED CHOICE.  When it involves detecting a coin's original surface - there is only one choice.  If it is good enough for Bugatti...  

.

3 hours ago, VKurtB said:

If they are what I think they are, they are like this:

 

 

Either way, I’m still not a fan.

LOL.  Nope.  However, this goes into the light for "shows."

 

1 hour ago, RWB said:

What I'm attempting to do is understand Skip's equipment and methodology. He places a great deal of value in the results and I want to understand how the process compares with others, and mre important, identify aspects that might show us all how and why his approach is superior. That is, I'm not looking for judgements or decisions, but for the information necessary to objectively evaluate Skip's process.

 

1 minute ago, RWB said:

OK. When do you use your fluorescent light?

Are observations visual, with hand magnification, with a stereo microscope at 10x to 60x or some combination?

What, specifically, do you detect with it. Is the OTT fluorescent a different shape than the folded tube you mentioned?

How have you compared this to other light sources or methods?

Answered above?

[VKurtB]

Skip, you've been kind enough to treat my responses seriously, even when I've been snarky as all git out to some of yours, and I appreciate that more than you know. In that spirit, I want to ask a few more questions to be certain I'm not misinterpreting what you have written here.

1) You wrote, I believe (some interpretation on my part) that back at your office, the fluorescent lamp you are using is a GE SP35 lamp. When I search that term, I get a 36 inch long, 1.1 inch diameter, medium bi-pin at both ends standard T8 shaped office-style fluorescent lamp and you use that to illuminate the stage for your stereo microscope, for which you have crafted a "hole" or "space" in the fixture's hood. Is that what you're saying, and how far from the scope stage would you say that is?

2) and others can wait. We'll start with 1) first.

Edited September 8, 2020 by VKurtB

[VKurtB]

Here is my "off the cuff" excessively snarky first impression:

It sounds like what you want to do is not "grade" coins, but "downgrade" them instead.

[RWB]

47 minutes ago, Insider said:

Apparently, this explanation was not posted in this thread.  I have ALWAYS had two lights on my desk.  A large 2 bulb florescent jewelers bench lamp with a cut out to shove a stereo scope into the shade.  A coin lamp as seen at shows and grading rooms with a 100W incandescent light bulb.  With most coins, I take the coin out of its flip and look at it under the light bulb, then I look at it using a 7X hand lens.  Next it goes under the zoom scope at 7X and I use florescent light.  Then I look at it under the incandescent AGAIN with my unaided (nearsighted) eyes.  All the while the little computer in my head has been taking notes and weighing what I've been seeing.  I see things under the scope (Remember that nothing can hide from florescent light if you tip and rotate the coin) that are detracting but MANY DON'T MATTER because you won't see them FOR SURE!   However, I alert the next grader and finalizer about what I saw in my notes.  Me, my company and every TPGS straight grades coins I wouldn't give away as a free gift.  It is called "commercial grading."  

I teach students to see EVERYTHING there is to see on a coin so that they can make an INFORMED CHOICE.  When it involves detecting a coin's original surface - there is only one choice.  If it is good enough for Bugatti...  

Answered above?

So, is this the type of light you refer to?

Edited September 8, 2020 by RWB

[VKurtB]

There's one advantage Skip has that I will never be able to match - nearsightedness. That can be a valuable asset to a numismatist. I'm about as presbyopia/farsighted as people get. If I take off my glasses and have a coin on a bench in front of me, I'm lucky to be able to FIND it.

Edited September 8, 2020 by VKurtB