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Author Topic: Some new online resources I'm building  (Read 1287 times)

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Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #25 on: January 01, 2022, 12:32:01 am »
Thanks Jay! Really hope you find something!

Cheers,

Steve
Steve Moulding
New York

Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #26 on: January 01, 2022, 12:45:27 pm »
I just tested it with a coin known to be in the Naville sale of the Bement Collection in 1924 (Naville VI Lot 98).
Hi Kevin, thank you. That was a great test! Just to show that coin in a chain I added the later sales that you found, so now we see all 4 appearances together as shown below (taken from the website https://www.rnumis.com/greek_coins_detail.php?dbid=CNG_20141217_88)

Steve
Steve Moulding
New York

Offline Anaximander

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Re: Some new online resources I'm building
« Reply #27 on: January 01, 2022, 07:25:46 pm »
How's this for a coin match to the rNumis provenance database:
Sicily, Selinus. 7.74 g., your Ars Classica XVI Lot 642. vs. my coin 7.86 gm, purchased from a dealer in Miami (yes, I get some mileage from having had a dealer in Miami  ;)).
 
I'll put down some of the weight difference to my being at sea level, or even below sea level, when taking the measure.
Chris “Anaximander” Thomsen. Member Since 2019.
My ForumAncientCoins gallery

Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #28 on: January 02, 2022, 12:19:55 am »
Hi Chris. It looks very good but that 0.12g difference is larger than I'd like to see. Not that it can't happen, of course, but I wish they were closer. I'm looking for a different sale that could confirm but as I don't have those in the database yet, it's the same time-consuming manual hunt.

Cheers,

Steve
Steve Moulding
New York

Offline Kevin D

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Re: Some new online resources I'm building
« Reply #29 on: January 02, 2022, 05:10:07 pm »
Regarding the reason early catalog coin images were produced from casts, I found this in my notes:

https://www.forumancientcoins.com/board/index.php?action=printpage;topic=102458.0


Title: Re: Old Auction Catalogue Madness!
Post by: Andrew McCabe on May 12, 2016, 05:12:48 am

Quote from: Molinari on May 12, 2016, 04:15:14 am
Why did they make plaster casts back then instead of just photographing the coins?

Good question.

It provides far better photos (the bad exception above is NOT typical), labour costs were low a century ago, and in advance of photoshop and digital cameras, the chances of getting a direct photo even remotely good were minimal - imagine photographing your coins today in the absence of preview screen - whereas plaster cast photography was a known reliable technique. Also, photographic printing costs were then very high indeed (using a lot of silver) so if you were going to spend a lot of money photographing just a few coins - they always selected just the best coins rather than photographing everything - and the cost was anyway going to be high, you might as well spend the extra to make plaster casts and make the photos as good as possible. Furthermore, to make up the plates needed a second photograph - of the photos sitting on the background of the plate with numbers under (again, in advance of photoshop) using a copy stand. Evidently if you start with prints and then have to photograph those, they'll be a whole lot worse than starting with a sharp plaster cast. To see what "just photographing the coins" resulted in, you need only look at the Rheinhold Faelten 1938 Stacks sale - possibly the worst ever plates - and just about any catalogue from the 1970s which was after printing became cheap and labour costs for plaster casts became dear, but before photoshop allowed digital improvements; the 1970s represents the nadir of coin photography.

Offline Kevin D

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Re: Some new online resources I'm building
« Reply #30 on: January 02, 2022, 05:13:20 pm »
I just tested it with a coin known to be in the Naville sale of the Bement Collection in 1924 (Naville VI Lot 98).
Hi Kevin, thank you. That was a great test! Just to show that coin in a chain I added the later sales that you found, so now we see all 4 appearances together as shown below (taken from the website https://www.rnumis.com/greek_coins_detail.php?dbid=CNG_20141217_88)

Steve

Steve,
The Provenance Chain is a great feature, with all the info for every auction appearance just a click away.

Offline Kevin D

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Re: Some new online resources I'm building
« Reply #31 on: January 02, 2022, 05:16:52 pm »
How's this for a coin match to the rNumis provenance database:
Sicily, Selinus. 7.74 g., your Ars Classica XVI Lot 642. vs. my coin 7.86 gm, purchased from a dealer in Miami (yes, I get some mileage from having had a dealer in Miami  ;)).
 
I'll put down some of the weight difference to my being at sea level, or even below sea level, when taking the measure.

As Steve has said, usually the weights are closer. This could be just a typo error for the middle weight digit, in one listing or the other. Or, one of the scales could have been a tenth gram off.

Offline Anaximander

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Re: Some new online resources I'm building
« Reply #32 on: January 03, 2022, 05:20:38 pm »
I weighed the Selinus tetradrachm anew and got the same reading: 7.86 gm (or 7.87 gm, depending on how well centered the coin is on the scale).
Given that coin weights on my scale align with weights provided by coin dealers, my scale is reasonably accurate (picture attached). 

If my coin is the same as the one shown in the Ars Classical catalog of 1933, then the catalogers must have had an inaccurate scale (unlikely), some human error (most likely), or the difference in altitude (Switzerland vs. sea level) had a measurable impact.

Interesting to hear about the use of plaster casts in early catalogs.  It's all about the costs and difficulties of coin photography.  I was betting that getting both sides of a coin into one photoshoot was the cincher, back in the day.
Chris “Anaximander” Thomsen. Member Since 2019.
My ForumAncientCoins gallery

Offline Kevin D

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Re: Some new online resources I'm building
« Reply #33 on: January 03, 2022, 05:25:46 pm »

I note that many Glendining catalogs do not list the weight of the coins, which means other parameters would be needed for a database search.


I ran another test, looking for the same coin that I ran a test on previously. This time I left the weight unspecified, just entering Calabria and Tarentum. This brought up 10 pages of coins, 48 results per page. I found the coin in 3 minutes of looking, on page 5.

Even if the database were to be expanded many times over, known coin weight or not, this would still be a GREAT improvement on what I did to find this provenance originally.

Congratulations Dr. Moulding, on creating this successful and wonderful provenance research program.

Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #34 on: January 03, 2022, 07:50:07 pm »
If my coin is the same as the one shown in the Ars Classical catalog of 1933, then the catalogers must have had an inaccurate scale (unlikely), some human error (most likely), or the difference in altitude (Switzerland vs. sea level) had a measurable impact.

Hi all, I'd agree with Chris that human error is the most likely of those three explanations. I do see occasional mistakes Ars Classica catalogs. I think the weight drop due to the altitude of Lucerne (not very high) would be smaller than what we see.  Also, I believe their scales were probably ok. Looking at other lots, we see for example
Ars Classica XVI, Jul 1933 Lot 153 7.24g = Sotheby, May 1916 (Headlam) Lot 230 7.23g = Jacob Hirsch XXVI, May 1910 Lot 227 7.23g.
All within 0.01g of each other.
(https://www.rnumis.com/greek_coins_detail.php?dbid=ARS_19330703_153)

Steve

p.s. Very nice to see that coin as it is today on your scale!
Steve Moulding
New York

Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #35 on: January 03, 2022, 08:07:25 pm »
I note that many Glendining catalogs do not list the weight of the coins, which means other parameters would be needed for a database search.
Thanks, Kevin! I'm glad you're finding the website useful. Yes, you're absolutely right...some Glendining catalogs didn't record the lot weights. I don't know why. Thankfully, many do though. So, all that makes things a little more fun (=challenging), but not impossible.
Along the same lines, I sometimes see sales from other houses where they didn't record the weights of some the bronze coins, even when they've been plated at some expense. Curious.

Steve


Steve Moulding
New York

Offline Steve Moulding

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Re: Some new online resources I'm building
« Reply #36 on: March 11, 2022, 10:45:35 pm »
For anyone interested in the Provenance Explorer over at rnumis I've made a significant upgrade to the code, adding the ability to do Multi-Level filtering beyond the initial Region/Issuer/Weight/Metal.
This makes it much easier to spot lost provenances (I found 3 already today).

Also, searches can now be bookmarked.

So far, I've only tagged Messana lots at Level 1 (183 of them). It's going to be a very lengthy process to go through the 8000 or so current lots and tag everything, but at least you can now see how it works:

https://www.rnumis.com/greek_coins_top.php?gk_region=SICILY&gk_issuer=Messana&metal=All%20Metals&mgkdb_minwt=0&mgkdb_maxwt=9999&FL=1&FN=1

Thanks for the continued feedback and especially for the help that some of you have very graciously provided.

Cheers,

Steve

edit: The 303 lots from Velia (Lucania) are now also tagged
https://www.rnumis.com/greek_coins_top.php?gk_region=LUCANIA&gk_issuer=Velia%20%28Hyele%29&metal=All%20Metals&mgkdb_minwt=0&mgkdb_maxwt=9999&FL=1&FN=1
Steve Moulding
New York

 

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