Provenance, Attribution and Condition: The Due Diligence Behind Every Lot

Before a paddle is ever raised, a serious collector is not buying a painting, they are buying the evidence behind it. Art due diligence is the disciplined work of testing that evidence: reconstructing who has owned a work, confirming who made it, and recording precisely what condition it is in today. A generalist house publishes a one line provenance and a thumbnail condition note. A buyer grade approach reads ownership history, attribution language, condition disclosure and the marks on the back of the canvas as a single body of proof. This guide sets out the complete art due diligence stack for modern and contemporary works, from the attribution ladder to scientific testing and stolen work checks, so you can judge not only the object but the case made for it.

The essentials

• The Art Loss Register holds more than 700,000 stolen, looted and disputed items and runs over 400,000 due diligence checks each year for auction houses, dealers, museums and collectors.
• Attribution is a ladder, not a verdict: autograph, attributed to, studio of, circle of and follower of each carry a different evidential weight and a different price.
• The Getty Provenance Index publishes more than 2.2 million curated ownership records drawn from sale catalogues spanning 1650 to 1945 and household inventories from 1520 to 1880.
• Section 2.3 of the ICOM Code of Ethics for Museums sets the market benchmark for provenance and due diligence, anchored to the 1970 UNESCO Convention against illicit trafficking.
• LLB Auction rejects roughly 40% of submissions at intake, so any work that reaches a sale has already cleared a documented threshold.

What Art Due Diligence Actually Covers

Art due diligence rests on four questions, each answered by a different body of evidence. Provenance asks who has owned the work and traces an unbroken chain of custody from the studio to the saleroom. Attribution asks who made it, and grades the certainty of that answer. Condition asks what physical state the object is in, including every restoration it has undergone. Title asks whether the seller has the legal right to sell, free of theft, loan or estate claims. A complete art due diligence review treats these as one connected case: a flawless provenance cannot rescue a doubtful attribution, and a confident attribution means little if the title is encumbered.

This article covers the diligence a buyer should expect on a single lot before bidding. It does not value the work, predict its resale price, or treat art as a financial asset, judgements that depend on the market rather than on the evidence. The four pillars are best read as a single grid, not as a checklist worked top to bottom. The table below maps each pillar and the point at which it most often fails.

Read across the row, not down the column. A contemporary screenprint with an impeccable gallery invoice still needs a condition report that discloses fading at the edges, and a title check that confirms the sheet was never reported stolen. A weakness in one pillar is rarely cured by strength in another, which is why a single connected review beats four checks run in isolation. Everything that follows expands one pillar at a time, then shows how they converge on a yes or a no.

How Provenance Is Reconstructed and Verified

Provenance is the documented history of an artwork's ownership, exhibition and publication, from the moment it left the artist to the present day. It is the backbone of art due diligence because it does two jobs at once: it supports authenticity, since a work with a continuous record is harder to fake, and it protects title, since gaps are where stolen or looted works hide. The Art Basel and UBS Global Art Market Report 2026, compiled by Arts Economics, recorded global art sales of 59.6 billion US dollars in 2025, a rise of 4% after two years of decline, with public auction turnover up 9%. In a market that large, documentation is the difference between a confident bid and an expensive guess.

Reconstruction starts with the present owner and works backward. Researchers read the verso, search published catalogues raisonnés, and query open archives. The Getty Provenance Index publishes more than 2.2 million curated records drawn from dealer stock books, sale catalogues spanning 1650 to 1945, and European household inventories from 1520 to 1880, a primary resource for tracing older chains of custody. For the modern period, the International Foundation for Art Research built a dedicated Provenance Guide focused on the contested 1933 to 1945 years, before the organisation wound down its operations in mid 2025.

A disciplined reconstruction follows an ordered sequence, and each step is a point where a fabricated history tends to break:

1. Establish the consignor's chain. Confirm how the present owner acquired the work, with an invoice, a bequest document or a prior auction record.
2. Name every prior owner. Convert vague entries such as private collection into named individuals or institutions wherever the evidence allows.
3. Search the public indices. Cross check the Getty Provenance Index and museum exhibition histories for matching dimensions, titles and inscriptions.
4. Read the back of the work. Record every label, stamp and inscription on the verso, then test each against the written record.
5. Run a stolen work check. Clear the object against the Art Loss Register before the sale, not after the hammer falls.
6. Disclose the gaps honestly. State plainly where the chain breaks rather than papering over a missing decade with optimistic language.

The 1933 to 1945 window matters because it covers the period of Nazi era spoliation, when tens of thousands of works changed hands under duress. A gap there is not a footnote, it is a reason to pause and dig further.

The phrase private collection deserves particular suspicion, because it can conceal exactly the owner a buyer needs to see. A reconstruction that converts vague placeholders into named people and dated transactions is worth more than a longer chain padded with anonymous entries. Auction specialists treat unexplained jumps in geography, sudden appearances after a long silence, and round-number gaps aligned with the war years as prompts for deeper research rather than details to smooth over.

Sound provenance is also the foundation on which the next pillar stands, since the people who owned a work are often the people who can vouch for who made it. To see how the back of a canvas feeds this process, read our guide on reading the back of the painting.

The Attribution Ladder: From Autograph to Follower Of

Attribution is the judgement of who created a work and how certain that judgement is. Auction houses express it through a precise vocabulary, and each rung of the attribution ladder moves both the price and the risk. Reading that language correctly is central to art due diligence, because the gap between two adjacent terms can represent a difference of an order of magnitude in value, and the wording is chosen deliberately.

The price consequence is concrete. The same composition can sell as an autograph work, as studio of at a fraction of that figure, and as follower of for a small fraction again, while the physical object barely changes between the three descriptions. Because the label drives the number, the incentive to overstate is permanent, and the discipline of holding each rung to its evidence is what keeps a saleroom honest.

The conventional ladder runs from full certainty to loose association:

• Autograph, expressed as the artist's full name and dates, signals the house's view that the named artist created the work in its entirety.
• Attributed to indicates a probable but not certain hand of the named artist.
• Studio of or workshop of means a work produced in the artist's studio, possibly under supervision, but not necessarily by the master's own hand.
• Circle of places the work in the artist's time and orbit, by an as yet unidentified hand.
• Follower of describes a work in the artist's style, possibly of a later date, with no claim of direct contact.
• After denotes a copy of a known composition, of any date.

For living and recently active contemporary artists, the ladder compresses but does not vanish. A signed, dated and documented screenprint by a major Pop artist sits at the autograph rung; an unsigned variant of the same image, lacking paperwork, may slide to attributed to or lower. The single most common failure of art due diligence is the optimistic upgrade, where a consignor or a hopeful cataloguer nudges a work one rung higher than the evidence allows. LLB Auction never defends an attribution without provenance or a certificate, and never upgrades a rung to flatter a seller. Our detailed treatment of the full attribution ladder from autograph to follower of sets out the price implications of each step.

Certificates, Catalogues Raisonnés and Authentication Committees

Three instruments support an attribution, and they do not carry equal weight. A certificate of authenticity is a signed statement, ideally from the artist, the artist's foundation or a recognised expert, affirming that a work is genuine. A catalogue raisonné is the comprehensive, scholarly inventory of an artist's known output, compiled by specialists over years and treated by the market as the standard reference; inclusion in one is often the strongest single proof a work can carry. An authentication committee is a panel, frequently run by an artist's estate or foundation, that rules on disputed works and publishes its decisions.

The hierarchy matters to careful art due diligence. A certificate signed by an unknown party proves little, while an entry in an accepted catalogue raisonné, cross referenced to exhibition history, is hard to dispute. The International Foundation for Art Research maintained a dedicated Catalogues Raisonnés Database precisely because these works of scholarship underpin both authenticity and legal ownership at the same time. Committees have grown cautious in the past decade: several artist foundations have stopped issuing opinions altogether to avoid litigation, which paradoxically raises the value of a clean prior record and of inclusion secured before a committee closed.

The market has adjusted to this caution. Where a foundation has dissolved its authentication board, a pre-existing catalogue raisonné entry or a documented exhibition loan becomes the practical substitute for a fresh opinion. Buyers should read the date on every certificate and ask who, precisely, signed it, since the authority of the signatory, not the existence of the paper, is what gives a certificate its weight.

Buyers should also know the limits of paperwork. A catalogue raisonné in preparation is not yet authoritative, and a committee's refusal to rule is not the same as a rejection. When the documents conflict with the object, the object and its condition report win the argument. Our comparison of whether a certificate of authenticity or a catalogue raisonné carries more weight sets out which proof a buyer should prioritise when only one is available.

What a Professional Condition Report Discloses

A condition report is a structured account of an artwork's physical state, written by a conservator or specialist, that records every flaw, repair and intervention. LLB Auction issues a three page condition report on the works it sells, because condition, not hope, sets the boundary of what a buyer is acquiring, and it is the most overlooked layer of art due diligence. A report that reads as too good to be true usually is.

A professional report discloses the support and medium, the dimensions to the millimetre, and the results of examination under controlled light. Dimensions are not a formality: a sheet measured at 76 cm by 56 cm is a different edition from one printed at 90 cm by 60 cm, and the gap exposes a mislabelled lot. Ultraviolet fluorescence reveals retouching and later varnish, which glow differently from original paint; raking light, directed across the surface at a low angle, exposes deformation, lifting paint and canvas distortion invisible head on.

The vocabulary itself is evidence. The report distinguishes inpainting, restoration confined to areas of genuine loss, from overpaint, which covers original work and is a far more serious concern. It notes any relining, where a weakened canvas has been reinforced with a second support glued to the back, a common and acceptable treatment that nonetheless changes the object. For works on paper, the terms shift to foxing, the brown spotting caused by mould or metal impurities in the sheet, and light staining from years of past display. None of these defects necessarily disqualifies a work; an honest disclosure of them is precisely what protects the buyer. A 20% buyer's premium buys access to a sale, but the condition report is what buys confidence.

Framing and glazing deserve their own line. A work sold framed may hide tape, hinges or trimming at the very edges that become visible only once the sheet is removed, and a non-archival mount can stain paper over time. A thorough report states whether the work was examined in or out of its frame, because the two are not the same inspection. To decode every line of one, consult our guide on how to read a professional condition report.

Reading the Verso and the Role of Scientific Testing

The back of a painting often holds more evidence than the front. The verso, the reverse of the canvas and its stretcher, carries exhibition labels, gallery and customs stamps, auction lot numbers, inventory marks and the artist's own inscriptions, a layered record that, read in sequence, reconstructs a work's travels. A label from a documented exhibition that matches the catalogue is corroboration; a label that contradicts the stated provenance is a warning that outranks a confident front. Forgers reproduce the image and neglect the back, which is why specialists turn the work over first.

When documents and labels are not enough, science enters the room. Conservation laboratories such as CIRAM apply a tiered set of largely non destructive techniques. Infrared reflectography penetrates upper paint layers to reveal underdrawing and changes of composition that betray a copyist. Macro X-ray fluorescence, abbreviated MA-XRF, maps the elemental composition of pigments across the whole surface and exposes anachronistic materials; a pigment that did not exist when the work was supposedly painted is decisive evidence of a later hand. Carbon-14 dating can place the age of a canvas or paper support, and Raman spectroscopy identifies specific pigments and binders. A 2026 review in npj Heritage Science stressed that portable X-ray fluorescence works best in combination with other methods rather than as a single verdict.

Science is not ordered for every lot; it is reserved for high value works, contested attributions or suspicious results from the basic examination. For contemporary art, where materials are recent and well documented, pigment anachronism is rarer, but signature forgery and unauthorised editions remain live risks that imaging can help settle. Knowing when to escalate to the laboratory, and when the paperwork already answers the question, is a core skill of art due diligence. Our guide on when scientific testing enters the room explains which tests answer which questions, and what they cost.

Art Due Diligence for Restitution, Title and Stolen-Work Checks

Clear title is the part of art due diligence a buyer cannot afford to skip, because a stolen or restitutable work can be reclaimed years after purchase, regardless of the buyer's good faith. The first line of defence is the Art Loss Register, the world's largest private database of stolen art, which holds more than 700,000 items and conducts over 400,000 due diligence checks a year on behalf of auction houses, dealers, museums, lawyers and lenders. A pre sale search that returns clear is documented proof of diligence; a positive match stops the sale.

The ethical framework comes from the museum world and has set the standard the trade now follows. Section 2.3 of the ICOM Code of Ethics for Museums requires that every effort be made, before acquisition, to establish that an object was not illegally acquired or exported. It is anchored to the 1970 UNESCO Convention, which obliges signatory states to control exports of cultural property and to prevent institutions acquiring illicitly traded works. Private buyers are not legally bound by these instruments, yet the market increasingly judges them by the same benchmark, and a resale can stall if they were ignored.

Good faith is not a defence in every jurisdiction. In several legal systems a buyer who acquired a stolen work, however innocently, must return it to the original owner and then pursue the seller for compensation, sometimes decades after the purchase. A contemporaneous, documented search does not transfer that risk, but it proves the buyer met the standard of care and strengthens any later claim against the party who sold the work.

Three checks protect a buyer in practice. Title checks confirm the seller's legal right to sell the specific object. Estate and loan checks catch works that belong to an unsettled inheritance or are out on long term loan to an institution. Export and cultural property checks flag objects that may not lawfully leave a country. For inherited contemporary collections, where ownership is often shared among several heirs, these questions decide whether a lot can be offered at all. Our guide to the title and restitution checks that protect a buyer details each step in sequence.

Three Lots, Three Diligence Outcomes

Diligence is easiest to understand through worked cases. The scenarios below are representative composites, not records of specific sales, and the numbers illustrate the logic rather than describe a named work.

A signed screenprint, edition of 150, by a major Pop artist. The consignor produced the original gallery invoice, and the work appeared in the relevant catalogue raisonné. The verso labels matched the exhibition history, and an Art Loss Register search returned clear. The condition report noted minor light staining at the sheet edges, fully disclosed. Outcome: accepted for sale at a 10% seller's commission, with the buyer protected by a complete and consistent file.

An unsigned canvas attributed to a blue chip contemporary painter. There was no certificate, no catalogue entry, and a ten year gap in the ownership chain across the most important decade. Infrared reflectography showed an underdrawing inconsistent with the artist's documented method. Outcome: rejected at intake. No level of market demand justified defending an attribution the evidence did not support.

A sculpture inherited by three siblings. Authenticity was sound and the foundation had issued a certificate, but the estate was unsettled and one heir disputed the sale. Outcome: held until written consent from all parties cleared the title. Authenticity was never the problem here; title was, and title cannot be bid away.

A painting with a flawless invoice but a failed examination. The paperwork was immaculate and the provenance unbroken, yet ultraviolet light revealed overpaint across roughly 30% of the surface, none of it disclosed by the consignor. Outcome: returned to the consignor with a request for a full conservation history before any sale could proceed. Strong provenance did not survive contact with the condition report.

Each case turns on the same logic. Strong provenance does not excuse a weak attribution, a clean attribution does not settle a contested title, and an honest condition note protects every party at the table. This is the rejection discipline that defines serious art due diligence: the willingness to walk away when the evidence does not hold together.

How Rejection Discipline Filters Doubtful Works

Every check described so far converges on a single decision: accept the lot, or refuse it. Rejection discipline is the practice of treating refusal as the default whenever the evidence falls short, rather than as a last resort once a sale has already been talked up. The Art Basel and UBS Global Art Market Report 2026 recorded a structural rebalancing toward established artists and older market sectors in 2025, even as sales by contemporary art dealers stayed flat. In a market re-pricing risk, a documented willingness to decline is itself a form of protection for the buyer.

Doubtful works rarely announce themselves with an obvious forgery. They arrive as small inconsistencies that only diligence catches: a provenance that names a private collection but no person, a certificate signed by an expert no longer recognised, a verso label whose typography postdates the exhibition it claims, a condition report that quietly omits the ultraviolet examination. Any one of these can be innocent. Two or three together form a pattern, and a pattern is where a careful house stops and asks for more.

The filter works in stages, and each stage removes a different class of problem:

1. Intake screening. The submission is checked for a coherent chain of ownership and a plausible attribution before any photography or cataloguing cost is incurred.
2. Documentary cross-check. Invoices, certificates and catalogue raisonné entries are tested against one another and against the object itself.
3. Physical examination. The condition report and, where justified, scientific imaging confirm that the material matches the claim being made.
4. Title clearance. The work is run against the stolen art register and screened for estate or loan encumbrance before it is accepted.

A work that fails any stage is declined, not quietly downgraded a rung and sold anyway. LLB Auction rejects roughly 40% of submissions on exactly this basis, which means the lots that survive are not the ones with the loudest backing but the ones with the cleanest file. The whole point of art due diligence is to place the burden of proof on the work rather than on the collector, and rejection is the mechanism that enforces it.

For the buyer, this changes what a catalogue entry means. A lot offered by a house that refuses two works in five is a different proposition from a lot listed by a platform that accepts whatever is submitted. The screening has already been done, the contradictions have already been chased down, and the work that remains has earned its place rather than simply paid for it.

FAQ: Art Due Diligence Before You Bid

What is the single most important document in art due diligence?

No single document settles it; the strength lies in agreement between several. An invoice, a catalogue raisonné entry, matching verso labels and a clear Art Loss Register search corroborate one another. When one element contradicts the rest, that contradiction matters more than any single certificate, which is why diligence weighs the whole file rather than one page.

Is art due diligence different for online auctions?

The evidence required is identical; only the delivery changes. A reputable online house publishes the provenance, a full condition report and high resolution images of the verso, so a remote buyer sees what a bidder in the room would. LLB Auction runs timed sales of 7 to 14 days, which gives buyers more time to read the documentation than a live room allows, not less.

How far back should provenance go?

Ideally to the artist, but completeness matters more than length. For modern and contemporary works, the critical window is 1933 to 1945, the period of Nazi era spoliation, where any gap demands scrutiny. A documented chain with one honestly stated gap is stronger than a suspiciously seamless history with no supporting paperwork behind it.

Can a certificate of authenticity be forged?

Yes, which is why a certificate is weighed, not simply trusted. A certificate from an unknown signatory proves little; one from the artist's foundation, cross referenced to a catalogue raisonné, is far harder to dispute. Forged certificates accompany forged works, so the document is always checked against the object and its scientific examination.

Who pays for scientific testing of an artwork?

The house or the consignor typically funds testing when a work's value or a disputed attribution justifies it. Carbon-14 dating, macro X-ray fluorescence and infrared reflectography carry real laboratory costs, so they are reserved for cases where the basic file leaves genuine doubt rather than ordered as a routine step on every single lot.

What does a buyer's premium of 20% actually pay for?

The 20% buyer's premium funds the curation, the per lot due diligence and the published condition report that a generalist listing omits. At LLB Auction it also reflects the roughly 40% of submissions rejected at intake, the screening that means a surviving lot has already cleared a documented threshold before bidding opens.

How LLB Auction Clears the Threshold First

LLB Auction is a buyer advocate first and an auction house second. The model is built on saying no: roughly 40% of submitted works are rejected at intake, so the curation is the product and everything else supports it. Three commitments turn that philosophy into concrete protection for the collector.

Per lot due diligence. Every work offered passes a documented review of provenance, attribution and title, including a pre sale stolen art check and verification of any certificate against the relevant catalogue raisonné. Nothing is ever described as more certain than the evidence allows, and condition is never stated as better than the report records.

Published condition reports. Each lot carries a three page condition report covering support, medium, dimensions and examination under ultraviolet and raking light, with every restoration disclosed. The report, not the sales copy, defines what a buyer acquires, and it is available to read before bidding.

Transparent, asynchronous sales. Four sales are committed across 2026, run as timed online auctions of 7 to 14 days on the house platform and also listed on Artsy. Fees are stated upfront: a 20% buyer's premium and a 10% seller's commission, with no costs added at checkout.

To follow the diligence behind each lot and receive sale previews with the full documentation attached, register for the LLB Auction newsletter and review the evidence yourself before you ever place a bid. That habit, applied consistently, is the whole of practical art due diligence.

Conclusion

Art due diligence is not a single test but a connected case: provenance establishes the chain of ownership, the attribution ladder grades who made the work, the condition report fixes its physical state, and the title and stolen work checks confirm the seller's right to sell. No layer rescues a failure in another, and the discipline lies in reading them together and walking away when they do not agree. In a market that reached 59.6 billion US dollars in 2025 according to the Art Basel and UBS Global Art Market Report 2026, the buyers who consistently acquire well are the ones who treat evidence as the asset. Master the full art due diligence stack, demand the documentation, and let the proof, not the marketing, decide your bid.

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À lire également :

• The attribution ladder from autograph to follower of
• How to read a professional condition report
• Certificate of authenticity or catalogue raisonné: which proof counts
• The back of the painting: how to read the verso
• When science enters the room: testing a contemporary work
• Restitution and title: the checks that protect a buyer

Sources :

• The Art Basel and UBS Global Art Market Report 2026 : Art Basel and UBS, by Arts Economics, 2026
• UBS Art Market Research : UBS, 2026
• Art Loss Register : Art Loss Register, London, 2026
• International Foundation for Art Research : IFAR, New York, 2017
• Getty Provenance Index : Getty Research Institute, 2024
• ICOM Code of Ethics for Museums, Section 2.3 : International Council of Museums, 2017
• Due diligence and good faith : ICOM Observatory on Illicit Traffic, 2021
• Scientific imaging techniques for art : CIRAM, 2025
• Portable XRF for paintings authentication : npj Heritage Science, 2026