What a certificate of authenticity covers, and how I catalogue every work
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A certificate of authenticity is a signed document that says a specific work — identified by title, catalogue number, dimensions, medium and year — was made by the named artist. One ships with every painting I sell, and the same facts sit in the catalogue so they can be checked later. It matters for insurance, for resale, and because an abstract painting can't be identified from a photo alone.
What's on the certificate
Artist, title, catalogue number, dimensions in inches, medium, year, my signature and the date of sale. For a two-panel work it lists each panel. The catalogue number is printed on the certificate and written on the back of the canvas, so the two can always be matched.
What it means legally, in New York
This isn't just a nice piece of paper. Under New York's Arts and Cultural Affairs Law (section 13.01), when an art merchant gives a non-merchant buyer a certificate of authenticity or a similar written statement, it is presumed to be part of the basis of the bargain and creates an express warranty for the material facts it states as of the date of sale. In plain terms: what I put on the certificate, I'm on the hook for.
How the numbering works
Every work I've released through the collective has a three-digit number, ABB-001 onward, given in the order it was catalogued rather than the order it was painted. The number is on the product page, in the SKU and on the stretcher. Numbers are never reused: when a work is destroyed or painted over — which happened to No. 035 in 2026 — the number is retired and the record kept. If you're ever offered a work claimed to be mine, the number is the first thing to check, and I'll confirm it by email.
What buying the painting does and doesn't include
You own the object. Copyright stays with me, which is standard and not a quirk of mine: under US copyright law (17 U.S.C. § 202), owning a painting is distinct from owning the copyright in it, and a sale of the physical work doesn't transfer the copyright unless that's agreed in writing. What it means day to day is simple — hang it, photograph it, sell it on, insure it as a named work; just don't make and sell reproductions of it.
What's recorded for each work
Title (or Untitled), catalogue number, width and height in inches, number of panels, year, medium, and where it was photographed. That record is what the product page draws on, so the dimensions you see are the ones on the certificate. No. 038, Never Enough, for example, is recorded as two panels of 30 x 48 inches, 2016, acrylic on canvas.
Why it matters for a venue or a business
Hotels, restaurants and developers who buy at volume need the paperwork for their insurer and, often, their accountant. Each work in a trade order comes with its own certificate and a one-page schedule listing every piece by number, size and price. Placement venues get the same schedule so the pieces on the wall can be matched against the labels.
FAQ
Is the certificate signed by the artist?
Yes, by hand, at the time of sale.
What if I lose the certificate?
Email the catalogue number and proof of purchase and I'll reissue it.
Does the certificate include the price paid?
No. Price is on the invoice; the certificate is about identity, not value.
Can I check a work's number before buying it second-hand?
Yes. Send the number and a photo to charles.s.black@gmail.com.
Sources
- New York Arts and Cultural Affairs Law § 13.01 — Express warranties — New York State, via Justia
- 17 U.S.C. § 202 — Ownership of copyright as distinct from ownership of material object — United States Code, Office of the Law Revision Counsel
About the author. Charles Black is a self-taught painter working in acrylic on canvas from a two-room studio at the back of a warehouse in Queens, New York, and the founder of ABB Collective. He has been posting the work as @abstractbyblack since 2022 and has placed paintings in bars, offices and private homes around New York. Questions about anything here: charles.s.black@gmail.com.