I don't know are there any more silly questions like this sort. But after Kenneth's response in the Chinese War Axe thread, I am getting fear of being foolish to recognise between fake and real artefacts (Especially for Chinese Ancient Weapons). I have never gone to search stuffs in ebay and then post in CHF since they are all deceptive. Thus I really need to know some techniques as well as tips to observe an artefact through images. (To Kenneth as well as Thomas Chen, since you are very expert in this area, did you have ever use the Radiocarbon dating technology in detecting a fake weapon, just similar to some grand European History in Discovery Channel).

(This thread is also important in gathering experience for even European Weapons as well)

Thanks a lot!!

To spot a fake might matter if it is in your hand, but otherwise you can trust the items in books that refer to the excavations of items. Some pictures of swords shown by enthusiasts however (such as one Chinese guy I encountered on the swordforum) are probably copied from some silly e-bay thing and then posted (and sadly boasted about) in ignorance.
When judging a picture of an item then just consider where it comes from, as with many things in life. Anything in the books I cite are comprised from British museum or Chinese museum items (and Yang Hong in 'Weapons in Ancient China' gives the find location of the items in his book) so they are a solid benchmark to some degree.
If there is no info, if it is a picture on the web, then you may need to use a little bit of reference material or experience.
Photo's can't alway provide 100% certainty but there are of course some when you can quickly see 'Yes' or 'No' at a glance.

For the most part problems with authenticity only count when you go to the market place to seek an ancient item out. Finding pictures of real ancient items is not as hard as actually finding real ancient items.
If you want to see pictures of real Chinese weapons, get a museum text or buy those few books with pictures of weapons such as I often refer to. Even the Osprey books at least have good pictures. There are other rare books, or Chinese language-only books, but 'Weapon in Ancient China' is availible in English and the obvious start.
Fakery is more a concern for a collector than a student however.

You can't radiocarbon weapons BTW, unless it is a wooden fragment attached to it, since they require an organic remain and use a date of death. Try a google search on C14 dating. TL testing is no good either.
X-rays and SEM or drilled samples can be used if the money wants to be spent for a laboratory test. They can spot fakes that may look OK to the eye. There are other tests, like using various solvents to detect artificial patina but generally an experienced eye needs to be developed and certain features looked for on the surface of the bronze.
Purchasing a mass of cheap coins, like common Han/Tang/Song coins (cast in the hundreds of millions per year over centuries) are so plentiful & can give a range of surfaces to study, and all sorts of corrosion. {see below********}
These at least teach a person how bronze looks if really from the Han period etc.. At the Taipei museum with GZ when we visited in March I enjoyed the patina colours as much as the bronze items, and also saw imprinted fabric imprinted on a bronze Zhou-era helmet. These are details I look for naturally by now, sometimes you need a good magnifying glass though.

I have shown pictures of features on bronzes, like several weapons threads etc, that would be useful to show how authentic bronze appears.
A few old non-weapon threads I include below, just for the surface pictures. Even the other weapons threads here have plenty of close details on bronze swords, hilts, arrowheads etc. to see.

If collecting bronzes, or wanting to know how a patina should look, a copy of Tony Allens 'Allen's Authentication of Ancient Chinese bronzes' is a good start and has many good suggestions to spot fakes.
http://www.allensantiques.com/
If eventually purchasing weapons or any bronze stay away from e-bay, in a nutshell, and expect to pay an appropriate amount for an item if it is real. Even if just looking at pictures you can assume it is all fake.
There is one guy, Jimmy, on e-bay who has real small & cheap bronzes like belt hooks and arrowheads but a random e-bay search would yield dishonest sellers.
There are only a few honest dealers out there on the web. Tony Allen is good but has very few weapons these days, being mainly Chinese ceramics in store.
Richard Nable is one guy who has real ancient Chinese weapons, being in the region of a few hundred to several thousand US$. he has good close pictures if you check.
http://www.trocadero.com/pricelesspast/catalog.html
Of material for sale though about 90% of material is fake, and on e-bay it is more like 99%


Join this group if you do want specific weapons discussion about artefacts and how to spot fakes. There are some pretty experienced people there, so perhaps do your homework before asking for answers like carbon dating of swords (!). They might be horrified by such a question. If you can google an answer first then there is no need to ask.
It is however a very good group.
http://groups.yahoo.com/group/Antiquities_Science/
There is also a group just on ancientweapons too, but is less active although always gets responses to questions on swords it seems. This include European weapons BTW.
http://tech.groups.yahoo.com/group/AncientWeapons/


I was asked about collecting a while ago and made this reply regarding the main issues;
http://www.chinahistoryforum.com/index.php...t&p=4869794



Threads
***********
crystals and minerals on bronze
http://z8.invisionfree.com/Bronze_Age_Cent...hp?showtopic=16

ancient coins & features of age
http://www.chinahistoryforum.com/index.php?showtopic=7769

Gold gilt studs & fabric imprints
http://www.chinahistoryforum.com/index.php?showtopic=6318

Oh Great, thank you for your advice Sir. Kenneth.

I'll try to think and do some researches in this aspect as well.

Might I ask you a few questions:

Ohm, I am sure that you are more interesting in Bronze items then iron ones (It seems that you're expert on Chinese Ancient Weapons, not later period of Han dynasty). However, if this still lie on your domain, could you give me some info about iron items as well.

In fact, I have researched upon many of your pictures and your links already. I recognise that through every of them, the colour of the surface could not be remained constant. Also, the surface area of some even shows rough due to corrosion and oxidisation.

I am sorry about the Radio carbon dating (I am researching this technique in the case of bronze drum found in Dong Son VN)

What happen if an artefact was found deep inside soil (burried for a long time ago), could archeologist use this technique to search the area around the artefact?



Thanks sir, however, if tests and techniques above left some permanent changes in a real prototype, what would happen then?

Here is another image I got from a detachment of that museum, this prototype did not exhibit in there

We may be on the brink of a revolution in dating swords. So far it has been a matter of judgment for metallic objects, but this paper shows a usable technique for C14 dating iron artifacts.

http://radiocarbon.library.arizona.edu/rad...application/pdf

Of course it only really useful if the carbon source is from charcoal rather than fossil coal. This very informative article on Chinese steel production explains that coal could not be used for swords, so there is hope for reliable dates.

http://www.staff.hum.ku.dk/dbwagner/MingFe/MingFe.html

Josh

PS. Be careful of the Jimmy seller. He sells real things and fakes. Sometimes he labels his fakes and sometimes he doesn't, and the real things may be from a different time period than he states. That said, I bought a Han dao from him very cheaply.

Yup, the same statement from bucketball also. Finally I may need to list best trusted museum in the world and pin it to my working table. The Cosmopolitan Museum Of Art and The Hermitage Museum in Saint Peterbourg are my most favourite place.

In dating metal artefacts many techniques can be used on items in association with the object, like bone, wood, ceramics.
BTW C14 dating on a site in Thailand yielded a controversial (and contested) date for bronzes that put them earlier than the first bronzes in China so just how secure a date is would depend on how certain the objects are all related.
i.e test the skeleton buried with a sword via C14, or a ceramic vessel using thermoluminescence dating. http://en.wikipedia.org/wiki/Thermoluminescence
Just make sure the grave items all belong together, and the figure should reflect the truth.



Some effective laboratory tests will leave damage. A drilled sample for metal testing could be on a discrete place though. It gives a % for the alloy that may reveal a fake (or not).
A cut section through a bronze is supposed to ID a fake 100% under microscope examination since a patina grows from inside the metal rather than just being a surface layer, but cutting a piece is obviously not an option in many cases.
Of some surface testing, X-rays or SEM (Scanning electron microscope) there is no damage.

Flame testing of a patina, & ID of the mineral (say copper/malachite) just needs a little bit of the corrosion as a sample and will reveal if the patina is not part of the object.

Of using solvents like Acetone or paint strippers etc. there is no damage to real patina (I test these things first on coins!) but a fake sometimes will show the effects.
Even a red hot pin on a fake resin patina is a trick that can be used.

I stick to items that have other signs of authenticity though so I have not payed out for a lab test of any sort. It isn't nessecary. Of the few items I am not 100% about I am just honest about my doubts and the expense of such testing is not justified for those pieces anyway.
I only buy items I am 100% sure of in the first place, so the ones I am not sure of are mainly gifted pieces as a matter of fact. No huge concern.




The picture you show is identical to an example in the British museum shown in Jessica Rawson's 'Art & archeology in Ancient China'.
The 'finial' or Dhun at the base of the pole seems to be the exact same item (literally the same one), and the halberd is likely the same just turned to the opposite side to my text picture.

When you say 'that' museum do you mean in Vietnam?
The reason it wasn't on display there but might be in a brocure is because the item is in the UK.
It's real enough, and from the Warring States period. Quite distinctive.





josh stout
Yesterday, 12:27 PM Post #4

For dating the earliest of iron objects this could yield useful information. Come to think of it I had heard of this idea before but didn’t know it was practical to extract, or ever heard of it being used. C14 dating as you have rightly pointed out would only be of use when ‘fresh’ charcoal was used in the item, and can be sampled (the report says the extraction method is 100% efficient!). It certainly sounds like a technique that could yield some very interesting information in the right situation.
Given that c14 dating can be contaminated just by bacteria on the hands of people who handle an object thereby skewing an age result I would think iron dating is another tool for a ballpark figure, but one that has its own complexities to be learnt. The margin of error of >+/-30 years given in the abstract of the Arizona report sounds kind of optimistic given results of testing on archaeological cooking fires I am aware of. I will need to read the report a bit closer.
Thanks for bringing it to my attention.
The paper by Wagner suggests the production of charcoal at the capital began during the Ming, and that earlier periods there was use of ‘charcoal iron’ from the south. If the item is older than Ming then it would be hit or miss whether a certain type of coal was used in the whole process. Whether mineral charcoal was used in processing ore rather than the final stage refining is another point in the making of ‘best’ weapons steel. Before this quite late period it would seem likely mineral coal would have been important in iron production. It notes that;
..."that the establishment of a state ironworks at Zunhua was necessary at the beginning of the Ming to provide high-quality iron to the armouries of Beijing. In north China at this time iron was normally produced using mineral coal as the fuel, and this iron would have had a sulphur content which was too high for the best weapons. Charcoal iron was necessary, but could only be obtained from the south. At the beginning of the Ming dynasty the supply routes from the south could not be relied on, and it was necessary to establish state production of charcoal iron near the capital, regardless of how costly it might be. "

In earliest periods whether the effects of mineral coal were really known is unlikely since there was a long learning curve. The Arizona reports says Chinese used coal after the 4th century AD.
If this were true then the ancient iron could be dated even if the effects of mineral coal were not appreciated in early ironwork, assuming 'old' wood wasn't used in the item.
In the processes to produce superior weapons steel in the Han period and after (several stages of refining) there were 2 points at which carbon entered the iron. The first high carbon % was from the initial production of pig iron. This was then bought down to a tiny % by heat decarburization and then refined by raising % by either forge working, or at the end & following the Han period by combining with pig iron to produce a mid-carbon steel. Whether mineral coal was always avoided from the start, or only in the end process for weapons would be another complication because the statement by Wagner above is not clear. I haven’t read the article thoroughly and will set some time aside to do so. Thanks for the link. I like his stuff. Of the Ming period I know basically nothing, yet it gives insight into earlier processes too.



His stuff is cheap. It's a good start. I have been told he sold one expensive fake to a collector who returned it for a refund, and some of his other items I think I wouldn’t trust just on faith. Even of those I can’t tell either way I just recognize the element of doubt. Of the small items of bronze he has they look good to me though, and given the items I buy I minimize my risks. The bronzes I have bought are all ancient, and his iron swords were good too. I saw he had a few iron dao in the past. I kind of hope he gets some more too.
I kind of doubt his ceramics though. It's not my field, but I bet Tony Allen would say a thing or two if he looked at the Tang horses or Han figures etc.
When I have gone so far as to give a shop link to somebody who might end up buying something I have suggested they e-mail me to check the item before they buy however.
Certainly the cheap & damaged bronze stuff is ‘good’. In the past also he tended to have more weapons of note, and one of John Piscopo’s and a couple of Chad Herringtons I have ended up with and they were all authentic too.
Still, yeah, he {probably} makes a few mistakes or doesn't know any better (**even based on some identifications he makes). Buyer beware of course. Compared to the other sellers on e-bay though he is still the only person who regularly has real cheap bronze items.

Sorry Sir Kenneth

It is a brochure, but all in Vietnamese, can't understand, it says: Mẫu vật từ Anh Quốc, Luân Đôn.

Let's me ask bucketball, he might know this line, he is a Vietnamese anyhow.

Specimen (sample) from London, England.

Thanks, make sense now to me.

BTW, do you have other pictures of that distinctive Ge in Great Britain.
I am so glad to be helped by you, sir.

They called that Ge as a Bird Chinese Halberd (rougly translated from Vietnamese), I cannot see the bird shape. The pole of this prototype seems to reflect a progress in Ge design in Warring States Period?

Thanks

I am new to the forum, and just came across this thread. Identifying Chinese forgeries, particularly bronze, is a big part of my job, so I would like to add a few comment.

As has already been mentioned, some forgeries can be readily spotted just by their patina, but this is generally not a reliable method of detection. Some notes on patina:

1) Be aware that chloride-based corrosion of copper and its alloys yields a very thick encrustation in a remarkably short period of time. Of the many fakes I identify, this is one of the most common patina that dupes unsuspecting buyers.

2) Chemicals can produce virtually any color of patina on bronze. I have used household chemicals to produce some very convincing surfaces, so do not think that it requires highly specialized materials!

3) Bronzes from certain regions of China, such as parts of Hubei, tend to have a very different patina than the red copper oxide and the blue and green alkaline copper carbonates and sulfates that tend to form in other regions. The surface can appear dull black or dark brown or, occasionally, shiny like freshly cast bronze. A metallographic examination of a removed sample will generally show that the internal corrosion is pretty advanced, despite the relatively minimal visible external corrosion.

Metallurgical analysis, to identify alloy composition, can be performed by any number of techniques, including XRF, SEM or the more exact related technique of EPMA (electron microprobe analysis), as well as drilling a sample for wet chemical analysis. There are some good databases for Chinese bronzes of the Shang and Zhou dynasties, though some lean more towards vessels than weapons. The database for Han artifacts is smaller, but several people are working on expanding it.

The composition of a tested item might fall so far outside the known parameters for authentic bronzes that you can be pretty well assured it is a fake. This is certainly the case when the alloy matches one of the modern standards. There are, however, a few pieces that have been proved to be ancient but which have very unusual compositions. There are also fakes made from remelted ancient scrap, so a composition that falls within known parameters is not necessarily an indication of authenticity.

The most reliable single method of authenticating an ancient bronze is a metallographic examination. Yes, this generally does involve removing a sample of the metal, but the sample can be pretty small. Depending on the artifact, a sample around 0.5mm square may be sufficient, though most samples are around 1.0mm square. As a scientist, the larger the sample the better, but you certainly want to avoid unnecessary damage to the artifact.

For those wishing to learn more about metallographic examination, [i]Metallography and Microstructure of Ancient and Historic Metals/i], by David A. Scott (Getty Conservation Institute, 1991, ISBN 0-89236-195-6), is a good book.

In rare cases, a lead-210 test might be desirable. Pb-210 is an isotope of lead with a very short half-life. If a sample of leaded bronze contains Pb-210 then the artifact cannot be older than, roughly, 100 years. Please be careful when sampling, as the corrosion products that form can contain Pb-210 from the surrounding environment. As a result, if you sample a truly ancient bronze, but get the corrosion products mixed in with the metal sample, you can throw off the results. Also note that the absence of Pb-210 in an object does not indicate antiquity, as the metal might never have contained and to begin with.

Radiography, such as an X-ray or CT scan, can be very useful in identifying some repairs, alterations and methods of manufacture. It is not uncommon for ancient bronze to have a mottled appearance on a radiograph, but some thinly cast pieces may appear rather uniform. Lack of mottling is not necessarily an indication of a modern piece.

In all, a combination of visual inspection, metallographic examination and metallurgical analysis can identify most Chinese bronzes as authentic or fake. I must stress that this authentication requires a combination of tests and examinations. All too often, I examine forgeries that have incorporated pieces of ancient metal at the locations most likely to be sampled. The microprobe and metallography may come back fine, but a radiograph can reveal the deception. This rule also applies to non-metals. Pottery forgeries are also being made from scraps of ancient material. A thermoluminescence (TL) test will yield an appropriately ancient result, but the item is a forgery. Don't depend on a single test!

As for C-14 of iron, we have used this technique to date an iron statue from the Tang dynasty, (this was one of several different tests and examinations performed). The results were spot on. The issue of charcoal vs. coal is critical, as previously mentioned. Without extremely reliable data on iron production from a given period and era, you may have to take you chances and run the C-14 before even knowing whether coal was used. Another drawback deals with the carbon content of the alloy. Even with AMS C-14, the sample size of a very low-carbon alloy might be bigger than you would want to remove from the artifact.

Tony Allen's book on bronze authentication was previously mentioned. I have corresponded with Tony about the book, as there are several significant errors in it. He is a most pleasant man, and the mistakes were innocently made, with no intent to mislead. Allen's "Authentication of Ancient Chinese Bronzes" was written with the best intent, but by a man who faced the daunting task of trying to become an expert in both Chinese bronzes and porcelain. Quite a job.

In his book, there are scientific errors, and some of the conditions sited as good evidence of antiquity are now known to be largely invalid. Similarly, some of the methods Mr. Allen describes as unreliable are actually among the best methods for identifying characteristics consistent or inconsistent with the proposed age.

The problem is that any hard science can be innocently misinterpreted or important features missed, and good scientific techniques may not be suited to all metals. You have to choose your scientific technique and your scientist carefully. Finding someone with extensive experience in the field of your specific antiquity is vitally important.

As for Mr. Allen's book, it was written with good intent and a true desire to protect people from purchasing a forgery, and I am in no way speaking ill of the man, his intent, or his business. I simply wish to report that some of the science in his book on Chinese bronze authentication is weak.

I hope that this information is of some use to people. The number of bronze fakes that I identify each year is disturbing. Worse, as scientific articles are published on methods of detection, the forgers learn to work around the science. I still think it is more important to teach people what science exists to identify suspect pieces, but it makes it very challenging to keep one step ahead of the dishonest folks.

Hi Melanie,
Could you explain where you work please? It seems you are working with unprovenanced artefacts so I am curious if it is for an auction house, private contract, or which institution etc.
You obviously work at the high end to be testing pieces by such diverse means.

About the errors of Tony Allen can you be specific?
I am aware that the fakers have learnt to attempt fake mineralised fabrics in patina, so his comments that this the best benchmark is out of date.
I expect his book may have a lot to do with that anyway, since it was published in 2000 IIRC.
The fake fabrics in a patina can be strained with the patina colour but they are not mineralised psuedo-forms I am told by those that encounter them.
The fakers do learn the moment something is published, that's for sure.
I have posted many pictures of psuedo-forms on this forum so if you care to examine any pictures then you will see quite a few on threads I have strarted on CHF ancient arsenals.

I am interested in the coaxing of patina from bronzes by chemical or electronic means. I do know they can form rapidly, even salt is the crude version and it can appear thick quite quickly.
Would you also say botryoidal formations can occur on fakes? In spotting electro-chemical forgeries one 'expert' cited suggested embayment of the patina and examination of the metal structure can give it away.

I think you would be most welcome on this group; http://groups.yahoo.com/group/Antiquities_Science/
The discussion there is entirely artefacts, and fakes and techniques would be topics of much interest.

Hi Kenneth,

I work for a US importer and dealer of Chinese antiquities. Part of my job is the scientific authentication of antiquities and the detection of forgeries. We really try to educate people about the science that is available, and the need to apply it. It is also important to us that the data be shared. The gap between archaeologists and other scientists, and the dealer/collector community is pretty big, but it can be bridged to some extent.

As for Tony Allen's book, I will have to reread it and get back to you, but the example you cited is one issue. I recall that there were also some misidentified features in several radiographs. As has been stressed, mistakes can be innocently made by anyone, AND what we know to be inaccurate now might not have been when the book was first published. Where the radiographs are concerned, it is possible that a radiographer gave Tony incorrect information. Someone trained to read images of modern materials might easily misinterpret the features in ancient metals. One common error is describing features as repairs when they are actually alterations (work that alters the original form), or the object is a complete pastiche.

As for mineralized fabrics and pseudomorphs, truly ancient artifacts do occasionally retain permineralized, as opposed to fully mineralized, fibers. Thus, the fact that not all of the material is truly petrified is not necessarily an indication of forgery. The forgers can stain fabric, and can permineralize it with relative ease, but I am unaware of any successful attempts to produce a true pseudomorph. As such, based on the current information, if the fibers are actually petrified, and there is no evidence that scavanged fibers have been attached, that feature can be seen as strong evidence in support of antiquity.

I have not conducted enough experiments on the production of induced patinas to comment on botryoidal formations. Thus far, I have not encountered any convincing formations of this morphology on a forgery, but that does not mean they don't exist. One thing that I have encountered is the attachment of scavenged corrosion products (including mineralized fibers) not by adhesive but by patination chemicals. The induced patina forms in such a way as to anchor the fragments, some of which retain their original morphology. Crushed fragments are pretty easy to spot under magnification, but this kind of fakery is of a higher quality.

A metallographic examination is required on most every bronze I study. On some pieces it is conducted in situ by polishing an edge to a sufficient depth to get past the encrustation and the outer zone of corroded metal. The best technique is still to study a small removed sample, but not all artifacts can be handled in this manner. It should be noted that in situ polishing often leaves are more noticeable mark than removing a sample.

The Antiquities_Science group you mentioned is another forum I recently joined. I am always looking for people interested in scientific examination of artifacts. Should be a good educational opportunity.

Best wishes,
Melanie

Thanks for your thoughts, and you should find some of the daily digests of the yahoo group of interest.
It is an attempt to get archaeologists and collectors together, but given the modern & contrived issues between them I expect limited results. Some archaeologists may find commenting on private owned items unethical.
An admirable effort though to bring the groups together since the basic joy of the ancient is the same, and to date there is one archaeologist who has shared excavation pics and artefacts although the rest of the posters are apparently collectors.
Getting the many lurkers involved is the challenge, and hence we are very hush-hush about the market aspect there.
....or at least I try to be.

Re; the techniques outlined above.
The level of fakery is of course proportionate to the item being sold, and where rare vessels retail for $30,000 or so I can well expect that a composite of vessel parts then given transplanted patina materials, and manufacturing minerally & visually correct surface treatments would pay rich dividends for the time involved. The fake would justify itself being a real masterpiece instead of a green paint tourist knock-off. Of course to spend even $1,000 to test such an item would be good sense.

Tony may not have given a complete guide to collecting issues and fake detection but he certainly did a service to collectors, especially of more accesible pieces. He did say judging authenticity by patina can be difficult, but as a start point there is really nothing like his book commonly availible.
He briefly dabbled in formal testing to be sure, and maybe was a bit dismissive of some, but generally his statements about limitations of various means to authenticate seem sound. (granted, fabric in patina is not 'sure' as he said IIRC, and he doesn't comment on patina crystalisation or several other relatively simple surface tests)
It might seem a bit simplified from a pure science point of view, i.e blue=azurite, but the worst that could be said perhaps is that while his methods are not a replacement for testing in pieces that justify it, as was not his contention IIRC, it would weed out at least many of the fakes that beginners are likely to encounter.
Since anything else for collectors would be dry academia on metallurgy I can easily see the book in it's context, i.e even pure academia seldom stays comphrehensive even after, say, 10 years.
It has rather more bright and glossy pictures than a Jstor article too!
This is not to refute anything you said of course, but just to have somebody batting for Tony's team.


PS; Good to have you here. Hope you stick around (although very little specifically on artefacts here as such). When I post pics here I will PM you anyway, or else I post links on the yahoogroup too.
I have some bronze weapons that have been held by NZ customs, I am applying for importation to proceed, but this takes maybe 6 weeks! I'll write something on them when they arrive.

Hi Melanie,

This is somewhat off topic, but I do research in condensed matter physics, and part of my interest is materials characterization. I was wondering how exactly you apply SEM analysis in alloy identification? SEM by itself is just purely a microscopy tool and cannot help in compositional analysis, unless it is equipped with some sort of EDS system. However, this still only gives a very basic elemental analysis of the material surface (for example, information about isotopes, or even empirical formulas of the material, would not be available). I'm not familiar with XRF or EPMA, so perhaps this is how the compositional information is obtained. Still, I can't see how SEM can provide any sort of meaningful information in alloy composition identification. From the tools I'm more familiar with, the more appropriate equipment to get this sort of information would be something like XPS or XRD. I'm really big on this sort of science stuff, so any information would be welcome. Thanks!

I'll e-mail Melanie to let her know you posted.
She writes very detailed analysis of artefacts and scientific methods on the AntiquitiesScience Yahoo group.
She is proffesional in every sense.

Dear wuTao,

Sorry for missing your post!!!! Thank you, Kenneth, for pointing out this message

For metallurgical analysis, the SEM is actually an EPMA (electron probe micro analyzer, aka EMPA electron microprobe analyzer), formed by using a dedicated SEM with, up to, five WDS detectors. You can analyze very large or small areas, depending on how you focus the beam. XRF (X-ray fluorescence) is another analytical method that is of great use, but is for more general analysis. The tested area is larger, and the limit of detection (LOD) is generally not as good as with an EPMA.

With either XRF or EPMA, it is possible to do calibrated analysis. When analyzing artifacts, rather than modern alloys, this is generally sufficient. You can determine whether the composition falls within the range for known authentic antiquities of that type and age. The analysis should be used in conjunction with a metallographic examination, as the composition alone is not enough to authenticate a purported artifact. Additionally, just because the composition falls outside the known range does not automatically mean the object is a fake. Again, the metallographic exam is necessary. There have been cases when an object of unusual composition has displayed significant internal penetration of corrosion that is completely consistent with natural long-term corrosion, rather than induced patination. Such objects are of particular interest, since they are anomalies.

One instance where analysis is particularly useful in the detection of forgeries is the presence of certain elements, such as phosphorous. Above a certain, relatively low, percent, this element is not generally found in authentic Chinese ancient bronzes (except as visible copper phosphide inclusions), but it is often encountered in forgeries. This appears to be due to the use of modern phosphor bronze to cast the object. You might also identify a high-quality reproduction among a group of items when the composition is too far off. For example, when a large set of objects is missing a few pieces, people have been known to make copies and patinate them to match the rest of the set. It is not unusual for the composition of the copies to be significantly different from the originals. Having such basic compositional data from an XRF analysis might prompt the examiner to do a metallographic study that will expose the copies.

Isotope analysis is not generally necessary in authentication of Chinese bronzes, though the data are of interest in identifying the location from which the particular element came. Generally speaking, if the source was from an impossible area (such as lead from the USA in a Chinese Shang dynasty bronze), there will be other aspects of the metal that will give away the fakery. Empirical formula are also not often needed, as the microstructure being studied is often easily identified. The vast majority of Chinese bronze artifacts will be alpha + delta. Nothing unusual. When you study tinned surfaces then it can become necessary to get the composition in order to identify the phase. You can zoom in with the EPMA and get the analysis for a single microstructural element and then use a calibrated analysis to identify the likely phase.

This is all a very basic explanation of the techniques. If it does not answer your question, please feel free to contact me again. You might try sending a personal message, since I seem to be pretty bad about missing important posts

Cheers,
Melanie

Hi Melanie,

Don't worry, your answer is exactly what I was looking for. Thanks for the information!