Provenance, Authentication and Condition
When Science Enters the Room: What Is a Certificate of Authenticity for Artwork Worth?
A certificate travels with almost every contemporary lot, and almost every buyer treats it as the end of the enquiry. It is a statement of opinion by whoever signed it, unregulated in every major market. Laboratory analysis answers from the other side of the same question.
A certificate travels with almost every contemporary lot, and most buyers treat it as the end of the enquiry. What is a certificate of authenticity for artwork, in evidential terms? A signed opinion carrying no automatic weight in law, worth what its signatory's standing is worth. Laboratory analysis answers the same question from the other side. Pigment identification, infrared reflectography and X-radiography read the object rather than the paperwork wrapped around it, and they answer a narrower question with far greater force: they establish what a work cannot be. No instrument names a painter. What follows sets out what each method reads, what it settles, and when its cost is proportionate to the lot in front of you.
Key takeaways:
- What is a certificate of authenticity for artwork under law? Nothing automatic. Robert Read, head of fine art and private client at the insurer Hiscox, told Artsy in February 2021 that most such certificates "are not worth the paper they're written on".
- Titanium white (titanium dioxide) reached commercial artists' oil paint in the early 1920s. In an original paint layer it dates that layer to the twentieth century or later.
- Radiocarbon dating now runs on a paint chip of under 200 micrograms, dating the act of painting rather than only the canvas beneath it (Hendriks and colleagues, PNAS, June 2019).
- Science subtracts. It disqualifies materials and dates, and it confers no authorship.
What Is a Certificate of Authenticity for Artwork, and What Does It Prove?
A certificate of authenticity is a signed declaration that a named work was made by a named artist. It is issued by the artist, by an estate or foundation, by the compiler of a catalogue raisonné (the scholarly inventory of an artist's complete accepted output), by a gallery or by a dealer, and the same label covers all of them. A declaration signed by the artist and tied to one specific object sits at one end of that scale; a slip printed by a reseller sits at the other.
The market has been retreating from the practice for over a decade. Sharon Chrust, then first vice president of the Appraisers Association of America, told Artsy in February 2021 that "several foundations stopped issuing certificates of authenticity back around 2012", naming Jean-Michel Basquiat, Andy Warhol and Keith Haring as artists previously authenticated that way, and adding that "certificates of authenticity can be forged just as well as the work can be forged". Impartial opinion has grown scarcer since. The International Foundation for Art Research (IFAR), which had run an independent authentication research service in New York since 1969, announced in September 2024 that it would close after 55 years. The consequences are traced in the authentication crisis now the boards have closed and in certificate of authenticity or catalogue raisonné.
What Is a Certificate of Authenticity for Artwork Expected to Contain?
A usable certificate identifies the work too precisely to be transferred to another object: full title, date, medium and exact dimensions; edition number and edition size for prints and multiples; a photograph keyed to the document by number or hologram; the identity, capacity and signature of the issuer with the date of issue; and the evidential basis, whether studio records, a catalogue raisonné number or a prior examination. Read's objection is structural rather than clerical. "You need to be able to link the certificate to the artwork over time for it to be of value," he said.
Pigment and Medium Analysis: Chemistry Keeps a Calendar
Materials analysis rests on one principle: every pigment, filler and binder entered the palette at a documented moment, and a material cannot appear in a work made before that material existed. X-ray fluorescence (XRF) excites the surface with X-rays and reads back element-specific signals, identifying titanium, zinc, lead, cobalt or cadmium without touching the paint. Raman spectroscopy and FTIR (Fourier-transform infrared spectroscopy) read the molecule rather than the element, which matters because copper appears identically in azurite, malachite and verdigris, three different pigments.
| Method | What it reads | What it can establish |
|---|---|---|
| X-ray fluorescence (XRF) | Elements in the paint surface | Anachronistic elements, such as titanium in a pre-1920 layer |
| Raman spectroscopy, FTIR | Molecular structure of pigment and binder | Which compound, which polymorph, which filler |
| Radiocarbon (AMS) dating | Carbon-14 in canvas fibre or paint binder | An absolute earliest possible date for support and for paint |
Resolution is finer than the market assumes. Corina E. Rogge and Julie Arslanoglu, in Science Advances on 17 May 2019, surveyed 109 oil paintings of known provenance made between 1926 and 1986 and showed that a luminescence signature picked up during routine Raman analysis flags titanium white coprecipitated with calcium or barium sulfate, narrowing the manufacture date of the pigment itself.
Radiocarbon analysis has moved to the same microscale. Laura Hendriks and colleagues, in the Proceedings of the National Academy of Sciences on 3 June 2019, dated two samples from a painting inscribed "Sarah Honn May 5, 1866 AD" and seized by the United States Federal Bureau of Investigation: a canvas fibre, and a paint chip of under 200 micrograms. The canvas was consistent with the nineteenth century. The binder was post-1950. The forger had repainted a genuinely aged canvas, which is why dating the support alone settles nothing.
Infrared Reflectography and X-radiography: Reading Beneath the Surface
Imaging reads process and construction rather than chemistry. Infrared reflectography (IRR) exploits the transparency of many dark paints to near-infrared radiation. The infrared band runs from roughly 700 to 4,000 nanometres; commercial infrared film responded up to 1,100 nanometres, while modern reflectography cameras record up to 2,400 nanometres. Charcoal and graphite absorb that radiation, so an underdrawing hidden beneath the paint photographs as a dark line. The method was formalised by van Asperen de Boer in Applied Optics in 1968. X-radiography passes X-rays through the whole object and images density differences, exposing pentimenti, the changes made mid-work, along with stretcher bars, tacking edges, staples and canvas weave.
On a contemporary work the questions shift. A 1970s acrylic on unprimed cotton duck frequently carries no underdrawing at all, so an empty reflectogram proves nothing. What imaging does deliver on post-war material is registration evidence in a screenprint, the staple pattern that dates a restretching, and, under ultraviolet fluorescence, the retouching an unaided eye reads as original surface.
What Is a Certificate of Authenticity for Artwork Worth Once the Laboratory Has Reported?
Science is an instrument of exclusion. It fixes a terminus post quem, the earliest possible date at which a work could have been made, which is frequently enough to end an argument. It cannot run the argument in the other direction. Jane Kallir, author of the Egon Schiele catalogue raisonné, set the limit in The Art Newspaper in November 2018: "Art authentication is not, and probably never will be, an exact science." In the same piece she noted that pigments unknown during an artist's lifetime expose a forgery, while historically appropriate materials do not prove authenticity.
The conservation scientist James Martin, who unmasked the Knoedler forgeries by demonstrating anachronistic materials, compares authentication to a three-legged stool of connoisseurship, technical analysis and provenance. Jilleen Nadolny, director of the United Kingdom offices of the laboratory ArtDiscovery, told Artsy that certificates "can become much more valuable when coupled with provenance and technical investigation: scientific analysis put into context with technical art history".
A clean report therefore means the analysis found nothing disqualifying, a weaker claim than authenticity and a different one. Where certificate, ownership history and technical report disagree, catalogue language moves down the attribution ladder from autograph to attributed to and studio of, and the estimate follows it.
When Testing Is Proportionate, and Who Pays for It
Cost sets the boundary. A full scientific workup at a leading commercial laboratory starts at roughly 13,500 US dollars per work, covering pigment and binder identification, elemental and molecular testing and radiocarbon dating, with a turnaround of about four weeks, according to the technical guide published by Masterworks Research in June 2026. Against a lot estimated at 3,000 euros that figure is absurd. Against a disputed painting at 150,000 euros with a decade missing from its ownership record, it is ordinary diligence.
Cheaper checks come first and resolve most questions. The Art Loss Register, founded in London in 1990, holds more than 700,000 items and runs more than 400,000 checks on works entering the market each year. Seven factors decide whether analysis goes further:
- Value at stake. The workup is proportionate below a few percent of the low estimate.
- Attribution risk. A closed authentication board and a heavy forgery record justify more.
- Provenance gap. An unexplained decade of ownership is the strongest single trigger.
- Medium. Editioned prints turn on publisher archives, not on pigment chemistry.
- Issuer standing. A studio certificate needs less corroboration than a reseller's.
- Sampling impact. Non-invasive imaging and XRF precede anything that removes material.
- Disclosure. Every destructive step is recorded and travels with the work.
That last point is codified. Clause 3.6 of the ICOM Code of Ethics for Museums requires that "when destructive analytical techniques are undertaken, a complete record of the material analysed, the outcome of the analysis and the resulting research, including publications, should become a part of the permanent record of the object". A private owner testing a work they intend to sell should hold to the same standard, because an undisclosed sampling scar found later does more damage than the original doubt.
On who pays: the consignor pays when the doubt attaches to their title, the prospective buyer pays for an opinion independent of the seller, and on higher-value lots a conditional arrangement in which the buyer commissions the test and the consignor reimburses on a negative finding is common. The laboratory reports to whoever instructed it. What is a certificate of authenticity for artwork commissioned by an interested party worth, then? Exactly what a technical report commissioned by that same party is worth, which is why who instructed the work belongs in the file beside the result.
How LLB Auction Handles the Question
LLB Auction rejects roughly 40 percent of the works submitted to it. The rejection is the product: a lot reaches the catalogue because its documentary trail held up, not because a certificate arrived with it.
Intake and rejection. Every consignment passes a per-lot review of certificate, ownership history and conservation records before acceptance. Four submissions in ten do not clear it.
Condition on the record. Accepted lots carry a three-page professional condition report. That report is the statement of record, and the house does not describe a surface as better than the report states.
Terms published in advance. Buyer's premium of 20 percent and seller's commission of 10 percent are disclosed before bidding opens, across timed online sales of 7 to 14 days.
Where a work warrants laboratory analysis, the lot notes say so and the instruction stays with the parties. The house documents; the buyer decides. Register at llb-auction.com to receive each catalogue before the sale opens, and see what registering to bid, identity checks and limits involves.
Conclusion
Testing a contemporary work is a decision about proportion. Pigment and medium analysis keeps a calendar and will disqualify a date outright; infrared reflectography and X-radiography read process and construction, and return little on a canvas painted directly; radiocarbon dating on a 200 microgram chip now reaches the paint layer and not only the support. Each excludes. None appoints an author. What is a certificate of authenticity for artwork after all of that: one piece of evidence among three, valuable in proportion to who signed it and how firmly it is tied to the object, and never the whole answer alone.
Also worth reading:
- Provenance, attribution and condition: the due diligence behind every lot
- How to read a professional condition report
- The back of the painting: how to read the verso
- The attribution ladder: autograph, attributed to, studio of
Sources:
- ICOM Code of Ethics for Museums : ICOM, 2017
- Certificates of Authenticity, Explained : Artsy, 2021
- Art authentication is not an exact science : The Art Newspaper, 2018
- Luminescence of coprecipitated titanium white pigments : Science Advances, 2019
- Uncovering modern paint forgeries by radiocarbon dating : PNAS, 2019
- Art Loss Register, About us : Art Loss Register, 2026
- IR Reflectography : ColourLex, 2026
- Forensic Analysis in Art : Masterworks Research, 2026
- IFAR to shut down after 55 years : ARTnews, 2024
