How coin scans can lie: Exhibit A

DennisH · February 22, 2003 2:29PM

Hello everyone! I thought that some of you who do not own a scanner might find this interesting (or perhaps scary):

Perhaps the best "help" I have received in buying coins though auctions and on-line, is the education that has come from scanning my own coins. Until you have done this yourself, I don't think you can begin to appreciate how impossible it is to accurately reproduce a coin. And the knowledge gained from scanning your own helps you "read" what may or may not be going on in the coins you view that have been scanned by others.

Here's an example using a coin I just scanned... same coin (1901-P MS62), same scanner, same settings. I rotated three of the scans so they all face the same way, I used "sharpen edges" on the composite 4-image scan to make things more clear, and I increased the brightness and sharpness a bit to more correctly depict the coin's whiteness.

Sorry, but I haven't learned yet how to attach my own links... the address of the scan to look at is:

www.members.aol.com/westdairy2/1901fourways.com

The only difference between the scans was where the coin was place on the scanner.

In the upper left scan, the light source in the scanner moved from the top of the coin to the bottom.
In the upper right scan, the light source moved from left to right across the coin.
In the lower right scan, the light source moved from the bottom of the coin to the top.
In the lower left scan, the light source moved from right to left across the coin.

Isn't it scary how different a coin can look simply by changing where you place it on the scanner?

Maybe someone else can share an Exhibit B or C of how scans can lie?

-- Dennis

solid · February 22, 2003 6:45PM

Link

Dennis, you should submit the scan in the lower right corner for upgrade...it's
definately MS63 or better!

Ken

TomB · February 23, 2003 2:11AM

That is very cool. A similar thing happens with toned coins in that you can get different colors to come out more brightly.

rkfish · February 23, 2003 12:15PM

That is very interesting!
Will have to give it a try myself!
Thanks!

solid · February 23, 2003 3:51PM

Tried it with my favorite Jeff nickel (1939-D Rev 38 ANACS MS67).

This coin doesn't have many marks to show (or hide), but you can definately see
how the orientation affects the detail clarity on certain areas of the coin. All scans
used identical scanner settings.

Overall, I like the top-left image best, with the sun shining on Jefferson's face

Ken

MoneyLA · February 23, 2003 6:50PM

Let me just add a note of disappointment about some scans of toned coins on eBay: many of the scans show up better than in reality, but in some cases the coins are better than the scans. So far, I have been disappointed with about half of my purchases, and overjoyed with the other half.

With that said, let me ask this -- since Im a scanner-incompetant: which position on the scanner is best for bringing out color?

cheers, alan mendelson

DennisH · February 24, 2003 12:01AM

Alan:

I have no experience with colored coins, but in terms of marks the best way to orient the coin in relation to the scanner's light source is literally different with each coin. Until you try all four different angles (plus there's a limitless number of partial rotations that can be tried), you'll never know.

Sorry there isn't an easier answer.

-- Dennis

solid · February 24, 2003 3:03AM

Alan, sometimes the best way to scan a toned coin is by propping up one
end of the slab a little. I used a 3.5" diskette, or about 1/8", under the
left side of the slab to bring out the colors in the nickel.

The upper scan is is propped, the lower scan is flat.

Ken

MoneyLA · February 24, 2003 9:03AM

Solid, thanks for the idea. I will give it a try. But to be honest, I think both scans are marvelous. cheers, alan mendelson

How coin scans can lie: Exhibit A

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