How the similarity check works
ArtSleuth's famous artwork detection runs a dedicated pass that compares your upload against thousands of documented masterpieces. For each candidate it returns a similarity percentage; the strongest match and two runner-ups are included in the final report.
The similarity score covers the full compositional and stylistic picture — subject matter, placement of figures, palette, and brushwork — not just a pixel-level match. That's intentional: a well-executed period copy may have been repainted at full scale with different canvas texture and it still needs to be identified as a copy.
Reading the similarity percentage
- 95% and above — almost certainly a direct copy, reproduction, or print of the named masterpiece. Value is typically in the reproduction range unless you have documentation that your copy is a period reproduction by a named artist.
- 60% – 94% — strong visual resemblance, which may mean a workshop copy, a student copy, or a contemporary painter deliberately referencing the original.
- 30% – 59% — same movement, period, or subject but not a copy. Often points to a follower or contemporary of the named artist.
- Below 30% — coincidence or shared convention of the era. Not a copy.
Why this matters for value
The difference in value between an original, a period reproduction, and a modern copy is often enormous — frequently 10× to 1000×. A high similarity score doesn't make your painting worthless; a documented, signed period reproduction by a known workshop can itself be a valuable collector's piece. What matters is knowing what you have before pricing, insuring, or selling it.
ArtSleuth's valuation engine reads the similarity score directly: if the painting scores above the copy threshold, the authenticity assessment is updated, and the valuation narrative explains what a documented reproduction of the specific masterpiece typically sells for in the current market.
What the report contains
- The best-matching famous artwork by name and artist, with a direct similarity percentage.
- Up to two alternative matches for context.
- A narrative paragraph describing the stylistic and compositional overlap between your painting and the top match.
- If applicable, an explicit Copy / Reproduction flag on the final attribution summary.
- A valuation range that separately reports the value if your piece is the original and the value if it is a copy.
Check your painting against famous artworks
Upload a clear photo and see whether your painting resembles a documented masterpiece — including which one and by how much.
Upload your artworkFrequently asked questions
If my painting scores 96% similarity, is it worthless?
Not necessarily. A 19th-century museum-quality copy by a named artist of a Renaissance masterpiece can be worth tens of thousands. What the high score tells you is: you do not have the original. Whether your copy is valuable depends on who painted it, when, and for whom.
Can the AI tell a print from a painted copy?
It flags candidate prints when the visible surface lacks the texture of brushwork and instead shows the regular dot patterns typical of lithography, giclée, or offset printing. High-resolution close-ups help the AI make this call.
Does this work for modern or contemporary masterpieces?
Yes — the reference set includes documented modern masters, not only classical works. Bear in mind that some contemporary works are deliberately released in numbered editions (prints, serigraphs); the AI flags similarity, but edition paperwork is how you verify authenticity for those.
Will this catch a forgery of an unrecorded work?
By definition, no. Forgeries of unknown works can only be caught by pigment analysis, dendrochronology, and provenance research. ArtSleuth handles the known-masterpiece case — which is by far the more common reason to ask 'is this a copy?'.