Ex-Numis Success Rate Question

Discussion in 'Ancient Coins' started by scarborough, Aug 18, 2021.

  1. AncientJoe

    AncientJoe Supporter! Supporter

    I submitted them a couple weeks apart (first from the auction photo and then after I received the coin) and each was independently processed. This is also not the first time a slightly different image has yielded different results for me; hopefully my account isn't just flagged as: "Sucker who will pay multiple times and upload marginally different images" :)

    I've used the Image Search feature of ACSearch a number of times which has been great at finding more recent pedigrees but it didn't find the Naville image automatically, probably because of the challenges in interpreting casts and other older photography techniques.
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  3. robinjojo

    robinjojo Supporter! Supporter

    Thanks for the link. An interesting article.

    I went through sort of the same situation with US Customs, but the issue was regrading a much lower value coin compared to John Nebel's coins. Fortunately, I did not need to retain an attorney, but Peter K. Tompa, did provide vital assistance.
    Last edited: Aug 18, 2021
  4. pprp

    pprp Well-Known Member

    I hope the reason was that they updated their photo database in between your 2 submissions otherwise this is quite worrisome. I assume their software returns some results ranked with a percentage of similarity and then someone needs to check manually the results. If this person is bored or does not check below 90% eg there may be missed positive matches :bored:
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  5. Silphium Addict

    Silphium Addict Supporter! Supporter

    The email I received after an unsuccessful search includes: “we will continue to search. As our Digital Recognition System learns and improves with time and as our database increases on a daily basis, we might get a positive match later on. In this case, we will contact you”
    So, the repeat submission by @Ancient Joe suggests that the submitted image does influence the results.
    My submissions are listed in my account, but I have never received any subsequent notifications over the years. So, I don’t know if all submissions are periodically rechecked. Has anyone ever received a later notification of a match?
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  6. Scipio

    Scipio Well-Known Member

    I tried the service a few weeks after it was released, spent some $$, got no result and no further notification.
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  7. pprp

    pprp Well-Known Member

    I got one, about a year after the initial submission they found a match to an old catalog. They missed some provenances out of my submissions. They probably missed others that I don't know yet. It's funny that I have coins that must have an old provenance which I can't find, while for others I found up to 5 different ones...
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  8. scarborough

    scarborough Well-Known Member

    After I wrote my original post, Ex-Numis advised me that their average success rate is in the 15 - 20% range.
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  9. Carthago

    Carthago Does this look infected to you?

    I submitted 30 excellent and high grade coins which almost certainly have been out of the ground for decades. I got 1 minor hit which I would have preferred not to even pay for.

    Some of these coins I have since found some great provenances in 20th century mainstream sales with my own research methods.

    Based on my experience, I am not a fan.
  10. Cicero12

    Cicero12 Supporter! Supporter

    This range seems highly unlikely to me. I would be skeptical of that
  11. Theoderic

    Theoderic Active Member

    After reading a previous 2019 thread on this forum about Ex Numis, I submitted 5 coins to them taking advantage of their introductory free offer as a test. All 5 were of high enough value that they likely would have been photographed even in older pre-digital catalogs, and they seemingly had been out of the ground for awhile so I thought the chances of success were pretty good. Unfortunately I only got 1 hit out of the 5 and even that was not very earth-shaking; a solidus I purchased from CNG in 2001 was traced all the way back to a NAC auction in 1999. I was disappointed but I still think the general idea is a good one. I hope they increase their database of old catalogs and keep improving the recognition technology.
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  12. Ryro

    Ryro The last of the Diadochi Supporter

    How long does it usually take them to get back to you once the coin has been submitted?
  13. red_spork

    red_spork Triumvir monetalis

    According to their website, submit pictures Monday-Sunday, get their reply on the next Tuesday, which lines up with the timelines I saw on the coins I submitted.

    Coincidentally, I very recently found a provenance via my own methods for a coin which I submitted to Ex-Numis and they found nothing for(this picture from CNG being the one I submitted):
    Roman Republic AR Quinarius(16mm, 2.28 g, 12h). Anonymous. After 211 B.C. Uncertain mint. Head of Roma right, wearing winged helmet ornamented with griffin's head and three-piece visor, earring an necklace; behind, V. Border of dots / Dioscuri on horseback riding right, each holding couched spear and wearing chlamys, cuirass and pileus surmounted by star; in relief in linear frame, ROMA. Line border. Crawford 45/2; Russo RBW 180; Sydenham 169.
    Ex CNG Triton XXII, 1/9/2019, lot 787, ex Alan J Harlan collection, ex Spink Numismatic Circular, April 1997, 1404


    While this isn't the best provenance, and I'll definitely continue searching, it's better than the 2019 date I had before for this coin. I was surprised when I found this because a number of public numismatic libraries have a full run of Spink Numismatic Circulars and I'd have expected Ex-Numis to have them.
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