CASE 006
:
THE CASE OF THE FORGED MASTERPIECE
A painting sold at auction for $4.2 million. The seller insists it is a lost masterpiece. The buyer insists it is a fake. One expert says authentic. Another says impossible. The canvas, the paint, and the light itself have been keeping a secret — and chemistry is about to reveal it.
CASE BRIEFING
On the morning of March 14th, a single lot brought the auction room at Harwick & Sons to silence.
Lot 47. Oil on canvas. Attributed to the Dutch Golden Age master Pieter van Hoorn. Circa 1668.
"River Landscape with Cattle" — a work that had not been seen in public since 1923, when it disappeared from a private collection during a period of political upheaval in Europe. Its reappearance after a century of absence was described by the auction house as a once-in-a-generation discovery.
The hammer fell at $4.2 million.
The buyer was a private collector — Helena Voss — who had commissioned two independent authentication reports before bidding. Both had declared the work genuine.
Twelve days later she filed a formal complaint with the Art Fraud Investigation Unit.
She had commissioned a third opinion — from Dr. Raymond Okafor, a forensic art scientist at the Institute for Cultural Heritage Analysis. His report arrived on a Tuesday morning. Helena Voss read it twice. Then she called her lawyer.
"The painting," Dr. Okafor had written, "is not what it claims to be."
The seller — a private dealer named Vincent Stahl — responded immediately and emphatically.
"The work has been authenticated by two of the most respected experts in Dutch Golden Age painting. Dr. Okafor examined it for three days. Whatever he thinks he found — he is wrong."
The two earlier authentication reports had focused on stylistic analysis — brushwork, composition, subject matter, pigment appearance under normal light. Both experts had concluded the painting was consistent with van Hoorn's known work and period.
Dr. Okafor had taken a different approach entirely.
He had not looked at the painting as an art historian.
He had looked at it as a chemist.
What he found divided the art world.
The painting had been submitted to a battery of scientific tests — X-ray imaging, ultraviolet fluorescence examination, infrared reflectography, pigment sampling, and radiocarbon dating of canvas fibers.
The results, Dr. Okafor said, told two completely different stories depending on which part of the painting you examined.
Vincent Stahl's legal team argued the tests were misinterpreted. Helena Voss's legal team argued they were definitive.
The Art Fraud Investigation Unit needed someone to determine which side was right.
That someone is you.
Your investigation begins now.
A painting worth $4.2 million. A seller who is certain of its authenticity. A buyer who is certain she has been deceived. And a forensic scientist whose report suggests the truth is more complicated — and more deliberate — than either side realizes.
Examine all five Evidence Files. The canvas has a story. The paint has a story. The light has a story. And somewhere in the chemistry of a 17th century Dutch masterpiece — or what claims to be one — the truth is waiting.
Not everything about this painting is a lie.
Not everything is the truth.
Your investigation will need to determine exactly which is which.
Instructions:
Play solo or with a team of up to 5 investigators. Examine the five Evidence Files together, or divide them among your team and have each investigator analyze different clues. Share what you discover, compare theories, and decide which evidence matters most.
When you've examined all the evidence, work individually or as a team to reach your final verdict—then reveal the solution to see if you cracked the case.
EVIDENCE FILES
EVIDENCE FILE 01 +
EVIDENCE FILE 01 — AUCTION HOUSE PROVENANCE REPORT
Case Reference: AFIA-2024-0314
Evidence Item: EV-01 — Provenance documentation and auction records
Prepared By: Investigator C. Marsh, Art Fraud Investigation Unit
Date: March 26
BACKGROUND
Provenance — the documented history of ownership of a work of art — is one of the primary tools used to authenticate paintings. A work with a clear, unbroken ownership record from artist to present day is significantly harder to forge than one whose history contains gaps.
"River Landscape with Cattle" has a provenance record that is both detailed and interrupted.
DOCUMENTED OWNERSHIP HISTORY
1668 — Pieter van Hoorn
The painting is attributed to Pieter van Hoorn — a minor Dutch Golden Age master known for landscape and pastoral subjects. Van Hoorn produced approximately 40 known works between 1655 and 1681. None are held in major public collections. His work trades in specialist auctions at modest prices — typically between $80,000 and $400,000 per work.
"River Landscape with Cattle" has never appeared in any catalogue of van Hoorn's known works. Its existence was unknown to the scholarly community until its submission to Harwick & Sons in January of this year.
1668 to 1887
No documented ownership record exists for this period — a gap of 219 years.
1887 — Acquired by the Brenner family
A bill of sale dated 1887 records the acquisition of a painting matching this description by the Brenner family of Vienna. The document names the seller as an unnamed private dealer and describes the work as "oil on canvas, pastoral subject, Dutch school, 17th century."
Investigators noted that the 1887 bill of sale does not name van Hoorn specifically.
1887 to 1923
The painting remained in the Brenner family collection. A photograph taken at the Brenner family estate in 1911 shows a painting on the wall of the main reception room. The image is low resolution. The subject matter appears consistent with a river landscape.
1923
The painting disappeared from the Brenner collection during a period of political and economic instability in Vienna. No sale record exists. No theft report was filed. The family later emigrated. The painting's whereabouts for the following century are entirely undocumented.
2023 — Vincent Stahl
Vincent Stahl submitted the painting to Harwick & Sons in January of this year. He stated he had acquired it through a private sale from an estate in the Netherlands and that the seller had requested anonymity. He declined to provide further details about the acquisition.
THE GAP PROBLEM
Art fraud investigators use the term "provenance gap" to describe periods in a work's history where ownership cannot be documented.
This painting has two significant gaps:
Gap 1 — 1668 to 1887: 219 years with no documentation whatsoever.
Gap 2 — 1923 to 2023: 100 years with no documentation — during which the painting allegedly passed through at least one private sale with no surviving record.
Both gaps are common in works of this period and history — particularly those that passed through European private collections during the upheavals of the 20th century. Gaps alone do not prove forgery.
However they do mean that the painting's history cannot be independently verified for the majority of its claimed existence.
VINCENT STAHL — BACKGROUND
Vincent Stahl is a private art dealer based in Amsterdam with 22 years of experience in Old Master paintings. He has no prior fraud convictions. He has sold works through major auction houses on fourteen previous occasions without dispute.
His refusal to identify the seller of "River Landscape with Cattle" is not illegal — private sale anonymity is standard practice in the art market.
It does mean that the chain of custody for the painting's most recent acquisition cannot be verified.
YOUR TASK
The provenance record for "River Landscape with Cattle" contains two significant gaps spanning more than three centuries of the painting's claimed history.
What does provenance tell investigators about a work's authenticity — and what does it fail to establish?
A forger who wanted to pass off a fake as a genuine 17th century Dutch painting would need to provide some documentation of history — but could not fabricate a complete record without risk of detection.
Does the provenance record as presented support the painting's claimed authenticity — or does it raise questions that the documentation alone cannot answer?
Research how provenance is used in art authentication and what the standard gaps and red flags look like in fraudulent works. Consider what a forger would need to do — and what they could not easily fake — when constructing a provenance record for a non-existent painting.
Then consider: if the provenance cannot confirm authenticity — what other evidence would you need?
EVIDENCE FILE 02 +
EVIDENCE FILE 02 — VISUAL AND STYLISTIC AUTHENTICATION REPORTS
Case Reference: AFIA-2024-0314
Evidence Item: EV-02 — Expert authentication reports — visual and stylistic analysis
Prepared By: Investigator C. Marsh, Art Fraud Investigation Unit
Date: March 26
BACKGROUND
Before submitting the painting to Harwick & Sons, Vincent Stahl commissioned two independent authentication reports from recognized experts in Dutch Golden Age painting. Both reports were provided to the auction house prior to the sale and formed the basis of the authenticity guarantee offered to bidders.
Investigators obtained both reports in full.
REPORT 1 — PROFESSOR ANNELIESE VOGEL
Chair of Northern European Art History, University of Utrecht
Specialization: Dutch Golden Age painting 1600–1700
Professor Vogel examined the painting in person for two days at Harwick & Sons' London storage facility in December of last year.
Her examination covered brushwork, compositional structure, subject matter, palette, and surface condition.
Key findings:
The painting's compositional structure — river in the middle ground, cattle grouped at the left, atmospheric sky occupying the upper third — is consistent with van Hoorn's known landscape formula as documented in his authenticated works.
Brushwork in the cattle figures shows the characteristic loose, confident handling found in van Hoorn's pastoral subjects. Professor Vogel noted specific similarities to brushwork in "Cattle at Rest near Delft" — an authenticated van Hoorn held in a private Belgian collection.
The palette — muted greens, warm earth tones, grey-blue sky — is consistent with pigments available to Dutch painters in the 1660s.
Surface craquelure — the network of fine cracks that develops in aged oil paint — is present across the entire canvas and appears consistent with a work of approximately 350 years of age.
Conclusion:
"I find no stylistic inconsistency that would cause me to doubt the attribution to Pieter van Hoorn. The work is consistent in every visual respect with his known production. I consider it authentic."
REPORT 2 — DR. MARCUS TRENT
Senior Curator, Department of Old Masters, Meridian Museum, New York
Specialization: Authentication of Dutch and Flemish paintings
Dr. Trent examined the painting for one day at Harwick & Sons in January of this year. His examination focused primarily on pigment appearance under raking light and the condition of the paint surface.
Key findings:
Examination under raking light — a directional light source that reveals surface texture — showed no areas of unusual flatness or inconsistency that would suggest inpainting or restoration over a fundamentally different surface.
The paint surface showed what Dr. Trent described as "natural, undisturbed aging throughout."
No areas of obvious retouching or restoration were identified.
The ground layer — the preparatory surface applied to the canvas before painting — appeared consistent with traditional Dutch preparation methods of the 17th century.
Conclusion:
"Having examined the work under multiple lighting conditions I find no evidence of modern intervention. The surface aging is consistent and convincing. I support the attribution to van Hoorn."
WHAT VISUAL AUTHENTICATION CAN ESTABLISH
Visual and stylistic examination by experienced experts is a valuable tool in art authentication. It can identify:
Inconsistencies in technique that suggest a different hand or period
Anachronistic compositional elements
Surface irregularities suggesting restoration or intervention
Pigment appearance inconsistent with the claimed period
What it cannot establish:
Visual examination cannot determine the chemical composition of pigments. It cannot date materials with precision. It cannot identify compounds that were not available in the claimed period. And it is inherently subjective — dependent on the knowledge and judgment of the individual examiner.
Both Professor Vogel and Dr. Trent are experienced and respected. Neither has any known connection to Vincent Stahl.
Their conclusions were reached independently and are consistent with each other.
YOUR TASK
Two highly qualified experts examined this painting and reached the same conclusion — it is authentic.
But consider carefully what their examinations actually involved.
Both experts examined the painting visually — under normal light, raking light, and their own professional judgment. Neither conducted chemical analysis of the pigments. Neither performed radiocarbon dating. Neither examined the canvas fibers under laboratory conditions.
What are the limits of visual authentication — and what questions can only scientific analysis answer?
Research the history of art forgery and how forgers have successfully deceived visual experts. Consider what a skilled forger who knew exactly what visual examiners look for might be able to replicate — and what they could not replicate no matter how skilled they were.
Then consider why Dr. Okafor — who also examined this painting — reached a completely different conclusion. His examination did not begin with the brushwork. It began with the chemistry.
What might the chemistry reveal that two experienced human eyes could not?
EVIDENCE FILE 03 +
EVIDENCE FILE 03 — SCIENTIFIC IMAGING ANALYSIS
Case Reference: AFIA-2024-0314
Evidence Item: EV-03 — X-ray, ultraviolet and infrared examination
Prepared By: Dr. Raymond Okafor, Institute for Cultural Heritage Analysis
Date: March 18
BACKGROUND
Scientific imaging allows investigators to examine layers of a painting that are invisible to the naked eye. Different wavelengths of light and radiation interact differently with paint layers, ground preparation, canvas, and any underlying material — revealing information about a work's construction history that no visual examination can access.
Dr. Okafor subjected "River Landscape with Cattle" to three imaging techniques over two days.
TECHNIQUE 1 — X-RAY IMAGING
X-rays pass through paint layers and are absorbed at different rates depending on the density of the materials they encounter. Dense pigments — particularly those containing lead — appear white on an X-ray image. Less dense materials appear darker.
X-ray imaging of authentic Old Master paintings frequently reveals pentimenti — evidence of the artist's changes of mind during the painting process. A tree moved slightly to the left. A figure sketched and then abandoned. An arm repositioned. These underdrawing revisions are a significant indicator of authenticity — a forger copying a known composition has no reason to change their mind because they are copying, not creating.
X-ray findings for "River Landscape with Cattle":
The X-ray image revealed a strong lead white ground layer beneath the painting — consistent with 17th century Dutch preparation methods.
The paint layers above the ground showed clear, confident execution with no evidence of significant revision.
No pentimenti were detected anywhere in the composition.
Dr. Okafor noted: "The complete absence of compositional revision is unusual in an original work of this complexity. It is consistent with a painter reproducing a known composition rather than creating one."
Vincent Stahl's response: "Van Hoorn was a disciplined painter. The absence of revision reflects his working method — not forgery."
TECHNIQUE 2 — ULTRAVIOLET FLUORESCENCE
When illuminated with ultraviolet light, different materials fluoresce — emit visible light — at different intensities. Old varnish fluoresces with a characteristic greenish glow. Fresh varnish applied within the last 50 to 100 years fluoresces differently — typically appearing darker or with a different colour tone. Restored areas that have been repainted also fluoresce differently from surrounding original paint.
UV examination is routinely used to identify areas of restoration and to assess the age and condition of varnish layers.
UV findings for "River Landscape with Cattle":
The varnish layer across the majority of the painting fluoresced with a strong, even greenish tone — consistent with aged natural resin varnish of significant age.
However Dr. Okafor identified one area of anomaly.
In the lower right quadrant of the painting — an area depicting water reeds and riverbank sediment — the UV fluorescence was distinctly different from the surrounding areas. The fluorescence in this zone was darker and less uniform.
This is consistent with either:
A restored area where original paint was damaged and subsequently repainted
An area where varnish was applied at a significantly different time from the rest of the painting
Dr. Okafor noted: "The UV anomaly in the lower right quadrant requires further investigation. It may indicate restoration — which is common in works of this age — or it may indicate something more significant."
TECHNIQUE 3 — INFRARED REFLECTOGRAPHY
Infrared light penetrates paint layers and reflects off the ground preparation beneath — revealing underdrawing. Many Old Master painters sketched their compositions in carbon-based materials before applying paint. Infrared reflectography makes these underdrawings visible.
Infrared findings for "River Landscape with Cattle":
Infrared examination revealed a clear underdrawing beneath the paint layers — fluid, confident line work defining the cattle, the riverbank, and the horizon.
The underdrawing style is consistent with known underdrawing characteristics in authenticated van Hoorn works examined by Dr. Okafor.
However — in the lower right quadrant, where the UV anomaly was detected — the infrared image showed something unexpected.
In this area the underdrawing appeared to stop. The paint layers in the lower right quadrant sat directly on the ground preparation with no underdrawing visible beneath them.
This means the lower right quadrant was painted without underdrawing — while the rest of the composition was painted over a clear underdrawing.
Two different methods of construction in the same painting.
YOUR TASK
Three imaging techniques have produced a complex picture.
The X-ray showed a consistent lead white ground and confident paint layers — but no pentimenti where an original work of this complexity would typically show some.
The UV examination revealed an anomaly in the lower right quadrant — different fluorescence from the surrounding areas.
The infrared examination revealed that the lower right quadrant was constructed differently from the rest of the painting — paint applied directly over ground with no underdrawing beneath.
What do these three findings — taken together — tell you about the construction history of this painting?
Is it possible for all three anomalies to appear in the same area of a genuine 17th century work — or does their concentration in one quadrant suggest something more deliberate?
Research what pentimenti tell authenticators about original versus copied works. Research why underdrawing is present in some areas of a painting and absent in others — and what that might mean.
Consider this question carefully: if the lower right quadrant was constructed differently from the rest of the painting — what are the possible explanations? And which explanation is most consistent with all three imaging findings combined?
EVIDENCE FILE 04 +
EVIDENCE FILE 04 — PIGMENT AND MATERIAL ANALYSIS
Case Reference: AFIA-2024-0314
Evidence Item: EV-04 — Chemical analysis of paint samples
Prepared By: Dr. Raymond Okafor, Institute for Cultural Heritage Analysis
Date: March 20
BACKGROUND
Following the imaging anomalies identified in Evidence File 03 — particularly the concentrated findings in the lower right quadrant — Dr. Okafor requested permission to take micro-samples from three locations on the painting for chemical analysis.
Helena Voss granted permission immediately.
Vincent Stahl objected. He was legally overruled by the Art Fraud Investigation Unit pending the outcome of the investigation.
Three samples were taken using a micro-sampling needle — each sample smaller than a grain of sand — causing no visible damage to the painting surface.
Sample Location 1 — Upper left quadrant — sky area — away from the anomaly zone — control sample representing the main body of the painting
Sample Location 2 — Centre — cattle figures — core subject area — second control sample
Sample Location 3 — Lower right quadrant — the anomaly zone identified in EF03
PIGMENT ANALYSIS — SAMPLES 1 AND 2
Samples from the upper left and centre were analysed using X-ray fluorescence spectroscopy — a technique that identifies the elemental composition of pigments without destroying the sample.
Pigments identified in Samples 1 and 2:
Lead white — the primary white pigment — consistent with 17th century Dutch painting practice. Lead white was the dominant white pigment used by European painters from the Renaissance through the 19th century.
Smalt — a blue pigment made from ground cobalt glass — widely used in Dutch Golden Age painting. Smalt was largely abandoned by painters after the 18th century when superior blue pigments became available.
Vermillion — mercury sulphide red — standard in 17th century European painting.
Natural ultramarine — ground lapis lazuli — expensive and prestigious — used selectively in high-value areas of Dutch paintings of this period.
Earth pigments — ochres and umbers — consistent with 17th century palette.
Assessment of Samples 1 and 2:
The pigment profile of the main body of the painting is entirely consistent with a 17th century Dutch work. Every pigment identified was available to a painter working in the 1660s. No anachronistic compounds were detected.
Dr. Okafor noted: "The pigment chemistry of the main body of this painting is consistent with the claimed period. If the entire painting showed this profile I would have no chemical basis to question its authenticity."
PIGMENT ANALYSIS — SAMPLE 3 — LOWER RIGHT QUADRANT
Sample 3 — from the anomaly zone — produced a dramatically different result.
Pigments identified in Sample 3:
Lead white — present — consistent with Samples 1 and 2.
Earth pigments — present — consistent with Samples 1 and 2.
Titanium white — also detected.
TITANIUM WHITE — WHY THIS MATTERS
Titanium white — titanium dioxide — is one of the most widely used white pigments in modern painting. It produces a brilliant, opaque white and is compatible with all painting media.
It was first commercially produced as a paint pigment in 1916 in Norway and expanded rapidly through the 1920s and 1930s.
Commercial production of titanium white for artists began in 1921 in Norway and expanded rapidly through the 1920s and 1930s.
It was not available to any painter working before 1921.
Pieter van Hoorn died in 1683.
A painting attributed to van Hoorn and dated circa 1668 cannot contain titanium white.
DR. OKAFOR'S ASSESSMENT
"The detection of titanium white in Sample 3 is unambiguous. This compound did not exist as a paint pigment until 1921 — more than 250 years after the claimed date of this work. Its presence in the lower right quadrant confirms that paint containing titanium white was applied to this area of the painting at some point after 1921.
This finding is not subject to interpretation. Titanium white is either present or it is not. It is present."
VINCENT STAHL'S RESPONSE
When informed of the Sample 3 findings, Vincent Stahl provided a written response through his legal team:
"The detection of titanium white in a small area of the lower right quadrant is consistent with restoration work carried out at an unknown point in the painting's history. Old Master paintings routinely undergo restoration — damaged areas are repainted by conservators using materials available at the time of restoration. The presence of a modern pigment in one small area does not invalidate the authenticity of the work as a whole. It simply indicates that area was restored."
YOUR TASK
The pigment analysis has produced a finding that cannot be explained away by interpretation or expertise — titanium white in the lower right quadrant of a painting claimed to date from 1668.
Vincent Stahl's explanation is restoration. It is not an impossible explanation — genuine Old Master paintings are frequently restored, and restorers do use modern materials.
But consider the imaging evidence from Evidence File 03 alongside this chemical finding.
The lower right quadrant showed:
Different UV fluorescence from the surrounding painting
No underdrawing beneath the paint layers
And now — titanium white in the pigment sample
Is restoration a sufficient explanation for all three anomalies concentrated in the same area? What would a restoration of a genuinely old painting look like under imaging and chemical analysis — and how would that differ from what Dr. Okafor found?
Research the history of titanium white and why its presence is considered a definitive dating marker in art forensics. Consider what the combination of findings in Evidence File 03 and Evidence File 04 tells you — not just about the lower right quadrant, but about the painting as a whole.
One question above all others: if the lower right quadrant was restored — what was there before the restoration? And if it was not restored — what was?
EVIDENCE FILE 05 +
EVIDENCE FILE 05 — CANVAS DATING AND FINAL FORENSIC ASSESSMENT
Case Reference: AFIA-2024-0314
Evidence Item: EV-05 — Radiocarbon dating and comprehensive forensic conclusion
Prepared By: Dr. Raymond Okafor, Institute for Cultural Heritage Analysis
Date: March 22
BACKGROUND
Following the pigment findings in Evidence File 04 — specifically the detection of titanium white in the lower right quadrant — Dr. Okafor requested radiocarbon dating of canvas fiber samples to establish whether the physical support of the painting was consistent with a 17th century origin.
Radiocarbon dating measures the decay of carbon-14 — a radioactive isotope present in all organic materials — to determine when a material was last living. Canvas is woven from plant fibers — typically linen or hemp — which stop absorbing carbon-14 when the plant is harvested. The ratio of carbon-14 to stable carbon-12 decreases at a known rate after that point — providing a measurable date range.
Canvas fiber samples were taken from the tacking margin — the edge of the canvas that wraps around the stretcher frame and is hidden from view — causing no damage to the painted surface.
RADIOCARBON DATING RESULTS
Two fiber samples were submitted to an independent laboratory under blind conditions — the laboratory was not informed of the nature of the investigation or the claimed date of the work.
Sample RF-01 — Canvas fiber — tacking margin left edge
Calibrated date range: 1620 to 1680 CE
Confidence level: 95%
Sample RF-02 — Canvas fiber — tacking margin right edge
Calibrated date range: 1635 to 1690 CE
Confidence level: 95%
Both samples produced date ranges consistent with a canvas prepared in the mid-to-late 17th century — entirely consistent with a genuine work from the period of Pieter van Hoorn.
DR. OKAFOR'S RESPONSE TO THE DATING RESULTS
"The canvas dating is consistent with a 17th century origin. This is an important finding — but it does not authenticate the painting. It authenticates the canvas. These are not the same thing.
A forger who wished to paint on genuine 17th century canvas would need to obtain one. Old canvases are available. Blank canvases from this period occasionally come to market when painted works are deemed too damaged to restore. Lined canvases — where a second canvas has been attached to the back of an original — can sometimes be separated. An old canvas provides a genuine radiocarbon date. It does not guarantee a genuine painting."
THE COMPLETE FORENSIC PICTURE
Dr. Okafor compiled his final assessment drawing on all findings from the three-day examination.
Finding 1 — Provenance
Two gaps totalling more than 300 years. The seller cannot identify the acquisition source. The 1887 bill of sale does not name van Hoorn. The painting does not appear in any catalogue of the artist's known work.
Assessment: Provenance is inconclusive. Gaps are significant but not unusual for works of this period and history.
Finding 2 — Visual authentication
Two experienced experts concluded the work is visually consistent with van Hoorn's known production. Brushwork, palette, composition, and surface aging all support the attribution.
Assessment: Visual authentication is supportive but not conclusive. Skilled forgeries routinely pass visual examination.
Finding 3 — X-ray imaging
No pentimenti detected in a composition of significant complexity. Consistent execution throughout suggests reproduction rather than original creation.
Assessment: Absence of pentimenti is notable but not definitive. Some painters worked with minimal revision.
Finding 4 — Ultraviolet fluorescence
Anomalous fluorescence concentrated in the lower right quadrant — consistent with paint applied at a significantly different time from the surrounding areas.
Assessment: UV anomaly is significant and corroborates other findings in the same zone.
Finding 5 — Infrared reflectography
Underdrawing present throughout the painting except in the lower right quadrant — where paint was applied directly over the ground preparation.
Assessment: Absence of underdrawing in one zone of an otherwise carefully underdrawn composition requires explanation.
Finding 6 — Pigment analysis
Main body of painting — pigment profile entirely consistent with 17th century Dutch practice. Lower right quadrant — titanium white detected. Titanium white did not exist as a paint pigment before 1921.
Assessment: The titanium white finding is definitive. Paint containing this compound was applied to the lower right quadrant after 1921. This is not subject to interpretation.
Finding 7 — Radiocarbon dating
Canvas fibers date to 1620-1690 CE with 95% confidence — consistent with a 17th century origin.
Assessment: The canvas is genuinely old. The canvas dating does not authenticate the paint layers above it.
YOUR TASK
You now have all five Evidence Files.
The canvas dates to the 17th century — genuine.
The pigments in the main body of the painting are consistent with the 17th century — genuine.
The brushwork, composition, and surface aging convinced two experienced experts — genuinely convincing.
But the lower right quadrant contains titanium white — a pigment that did not exist before 1921 — combined with absent underdrawing and anomalous UV fluorescence.
And the provenance cannot be verified for more than 300 years of the painting's claimed history.
Vincent Stahl says restoration. Dr. Okafor says partial forgery.
Using evidence from all five files — what do you believe happened to this painting? Is it a genuine van Hoorn with undisclosed restoration? A partial forgery on a genuine canvas? Or something else entirely?
Build your case. The chemistry has been pointing somewhere from the moment Sample 3 was opened. The canvas, the pigments, the imaging, and the provenance all have something to say.
What does the evidence tell you — and what does it leave open?
HAVE YOU SOLVED THE CASE?
Review the evidence and decide what you think happened. If you're investigating with others, discuss your findings and agree on your final verdict before revealing the answer.
Once your team has reached a conclusion, reveal the answer.