Verified as of 28 September 2026.
Before you pay, you should be able to answer four questions: what the piece is, who is entitled to sell it, what documentary history it has and what condition it is in. No single document settles all four on its own. Due diligence means checking that the work, the seller, the paperwork and the physical condition add up to a coherent story.
Identify the piece
Do not stop at the title. Record the attributed artist, date, technique, support, dimensions, signature, inscriptions, labels, inventory number and photographs of the front, back and details. The back may carry stamps, exhibition labels, shipping marks and old numbers.
If the object is an edition, check the edition size, the copy number, artist's proofs, the publisher and the technique. If it is digital, identify the file, version, edition, contract or token if there is one, technical dependencies and delivery method.
Check who is selling
Ask for the seller's identity and, if they are acting for another person or a company, the documents that show their authority. The invoice or contract must identify the parties and the work. A gallery may sell work it owns, hold it on consignment or act as an intermediary; these situations are not equivalent.
Also ask about co-ownership, undivided estates, pledges, seizures, deposits and known disputes. Someone having the work in their hands is not enough.
Provenance
Provenance is the history of ownership and custody. Gather invoices, contracts, inventories, catalogues, labels, dated photographs, correspondence and exhibition records. Gaps do not on their own prove anything irregular, but they increase the need for research.
Pay particular attention to periods of war, looting, clandestine excavation, illicit export or poorly documented changes of ownership. For archaeological or ethnographic heritage, or material from conflict zones, due diligence must be stricter.
Attribution and authenticity
Keep three things apart:
- provenance explains where the piece has been;
- attribution proposes who may have made it;
- authenticity assesses whether the piece really matches that attribution.
A signature, a certificate or inclusion in a catalogue may be relevant, but none should be accepted without examining who issued it, what authority they have and what documentation they rely on.
Condition
Ask for a condition report when the value, fragility or complexity of the piece justifies it. It should describe the support, surface, damage, previous interventions and include dated photographs. It does not prove authenticity or economic value.
Restrictions and rights
Check whether the work can leave Spain, whether it is protected or inventoried and whether it requires authorisation. Buying the physical object does not on its own transfer the exploitation rights. For works of visual art and photographs there is a specific rule allowing the owner to exhibit the original publicly, unless this was expressly excluded when it was transferred; reproducing, editing and publishing images remain separate matters.
Before payment
Get the following in writing:
- complete identification of the work;
- identity and authority of the seller;
- price, taxes, commissions and costs;
- declared provenance and the documents handed over;
- condition and known restorations;
- delivery and insurance terms;
- authenticity or attribution, stated precisely;
- export restrictions;
- rights or licences included;
- agreed remedies if an essential statement proves false.
Do not pay on the promise of documents to come unless the contract clearly makes the sale conditional on them and holds back part of the price.
On the open conversation
This guide sets out general due diligence and does not replace a legal, technical or physical examination of a specific piece.
If you spot an error, a broken link or a relevant change, write to me.