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Pillar of the Community
United States
4038 Posts |
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Moderator
United States
56855 Posts |
Can you direct link to pics please? John1  |
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Pillar of the Community
 United States
4038 Posts |
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
United States
56855 Posts |
Very cool  Is it time consuming to take pics like that? John1 |
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Pillar of the Community
United States
3546 Posts |
Hello, Very revealing and well-done shots. These photos appear to elucidate quite well upon the seldom seen granular infrastructure of a coin at the microscopic level. With this being said, I wonder if PCGS and NGC use this particular type of diagnostic aid to differentiate authentic from spurious when grading an added mint mark for example etc...? For instance, take a look at the initial photo illustrating the diagonal-positioned 'S' clip of the 1940SRPM7 on Ray's photobucket page: http://s943.photobucket.com/user/rp...l?sort=3&o=0At least from the perspective of this and the other two photos it appears that the granular striations are ever so slightly creeping up from the field only along the perimeter of the first 30% or so on only the W-NW side wall of the device. And I would guess that possibly only an electron microscope or 3D imaging as shown here would be capable of exposing this type of phenomenon. I have never delved into mint mark formations down to this exceedingly minute level but it would be of interest to know anyone could verify whether or not Chinese forgery artists, for example, have perfected their craftsmanship to precisely clone this type of aforementioned migratory infrastructure? mdpmedia |
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Moderator
United States
23522 Posts |
This is most definitely forensic-level optics, but there's probably no way one could generalize about the better minted counterfeits in the absence of a database of known dies literally impossible with Lincolns, for instance. A promising avenue of research, all the same. Me, I'm still not past the point of simply giggling at Ray's images; I'm not yet capable of doing serious research with them.  |
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Pillar of the Community
United States
4038 Posts |
John1...it does take some time. It takes a minute or two to frame the coin and optimize the lighting. The photo stack itself, typically 36 images, takes a few minutes to shoot, and the stack software takes about 10 minutes to render the 2D image, but both these processes are unattended. Adjusting the angles, rotation, zoom, etc of each 3D rendering takes a couple minutes, so from start to finish is perhaps 20 minutes, the majority unattended.
mdpmedia...thanks for the comments. Research like you describe is definitely interesting and rewarding. I'm pretty sure that most counterfeits would fall apart at this level of scrutiny. I'd really like to have a coin with known added mintmark, or other work done, to see if it is easily distinguished with this technique.
SD...me too, still giggling. These are really fun to do.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Valued Member
440 Posts |
Ray the imaging you do never ceases to amaze me. This would also be a great technique to image certain varieties like the sextupled star on a Morgan dollar. |
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Bedrock of the Community
United States
10045 Posts |
Wow--great use of focus-stacking to capture a sense of depth! Is that just focus-stacking or some kind of 3D software too? Edited by DVCollector
10/22/2014 11:07 pm
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Pillar of the Community
United States
4038 Posts |
Focus stacking just results in a 2-D image. It takes a 3D program to convert the depth map into a viewable 3D rendering.
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Bedrock of the Community
United States
10045 Posts |
 Are you saying you used 3D software as well--where did you get the relief data to map to the image? |
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Pillar of the Community
United States
4038 Posts |
The data comes from the focus stacking depth map. Pixels that are selected from each image are associated with a particular depth.
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Bedrock of the Community
United States
10045 Posts |
Wow--that's a pretty cool use for focus-stacking! Which stacking program generates that depth map--Helicon Focus?
Edited by DVCollector
10/23/2014 12:09 am
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Pillar of the Community
United States
4038 Posts |
Both Helicon and Zerene can be used. CZP may also do it, I'm not sure. Supposedly photoshop does it as well. There are also many 3D CAD programs capable of this and much more...Ray
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Pillar of the Community
United States
1374 Posts |
OMG. I'm stunned. I must do this. Help me get started guys!
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Pillar of the Community
United States
4038 Posts |
Sorry, but the setup I use for the 3D images was custom made for me, so I can't reproduce it easily. Note also that each of these is a stack of typically 36 images, and must be processed for depth map and then 3D rendering, so it is a time consuming process. I am not trying to discourage, just to inform...Ray
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Replies: 22 / Views: 5,011 |
Posted 10/19/2014 9:12 pm
