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JACOB GYBERG. Matsked, silver, Lund, 1810.

Jacob Gyberg · Silver and metalware · Helsingborgs Auktionskammare

Open auction lot
54
research

Acquisition position

Current all in cost

332.96 SEK
Current bid or estimate300.0 SEK
Modelled discount91.0%
Liquidity score84%

Potential market value

Specialist value interval

1010 to 13579 SEK
Value confidence70%
Comparable sales30

Evidence strength

39%
Identity confidence32%
Visual match0%
External references12

Market anomaly

84%
Information gap67%
Potential undervaluation91.0%

Risk profile

13%
Authenticity risk13%
Condition risk6%

Investigation rationale

Why this may be worth considering

  • maker or artist identity supplied
  • auction estimate is materially below the specialist model
  • all in acquisition cost is at least 55 percent below modelled value
  • all in acquisition cost is at least 75 percent below modelled value
  • Estimate materially below specialist value

Decision guardrails

What must be verified

  • category trap check: silver plate
  • missing hallmarks
  • missing fineness
  • missing weight
  • missing date_letter

Visual laboratory

Add and compare research imagery

Object record

Known facts and missing information

ArtistJacob Gyberg
MakerMissing
MediumMissing
MaterialsMissing
Dimensions? × ? × ? cm
WeightMissing g
YearMissing
EditionMissing
MarksMissing
ConditionÅldersslitage med gravyr.
ProvenanceMissing
Modelsilver_metalware_specialist 2.0.0

Längd 19,5 cm Vikt 35 bgram.

Identity resolution

Artist and maker hypotheses

Ranked from independent evidence. Confirmation or rejection becomes controlled training data.

7 candidates
1 independent sources

Constant Troyon (French, 1810–1865)

Visual 0% · Name 86% · Marks 25% · Material 40%

33% combined confidence
1 independent sources

Giovanni Battista Piranesi (Italian, 1720-1778) published by Francesco (Italian, 1758-1810) and Pietro Piranesi (Italian, born 1758/9)

Visual 0% · Name 86% · Marks 25% · Material 40%

33% combined confidence
1 independent sources

Jean Jacques de Boissieu French, 1736-1810

Visual 0% · Name 86% · Marks 25% · Material 40%

33% combined confidence
1 independent sources

Roger Fenton English, 1819–1869

Visual 0% · Name 41% · Marks 25% · Material 40%

25% combined confidence
1 independent sources

Creil Pottery French, 1801-1840

Visual 0% · Name 39% · Marks 25% · Material 40%

25% combined confidence
1 independent sources

Designed by Narcissa Niblack Thorne American, 1882-1966

Visual 0% · Name 38% · Marks 25% · Material 40%

25% combined confidence
1 independent sources

Henry Raeburn (Scottish, 1756–1823)

Visual 0% · Name 35% · Marks 25% · Material 40%

24% combined confidence

Closed deal feedback

Teach the valuation model

Enter the verified hammer price after the auction closes. Only verified outcomes become calibration data.

Learning guardrail

Truth before training

  • Unverified AI output is stored as a hypothesis only.
  • One-source matches are confidence capped.
  • Rejected matches improve source and feature calibration.
  • At least five verified closed sales are required per category.

Global research evidence

Reference material found elsewhere

12 references
Art Institute of Chicago

E-26: French Anteroom of the Empire Period, c. 1810

Designed by Narcissa Niblack Thorne American, 1882-1966

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

E-13: English Rotunda and Library of the Regency Period, 1810-20

Designed by Narcissa Niblack Thorne American, 1882-1966

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Unfinished Study of Sheep

Constant Troyon (French, 1810–1865)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

The Road to Market

Constant Troyon (French, 1810–1865)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Pasture in Normandy

Constant Troyon (French, 1810–1865)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

A Clump of Trees

Constant Troyon (French, 1810–1865)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

View of Ponte Lugano on the Anio, from Views of Rome

Giovanni Battista Piranesi (Italian, 1720-1778) published by Francesco (Italian, 1758-1810) and Pietro Piranesi (Italian, born 1758/9)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Old Man with a Boy Reading

Jean Jacques de Boissieu French, 1736-1810

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Tureen

Creil Pottery French, 1801-1840

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Sir Charles Ash Windham (1810-1970), General; taken at the Crimea

Roger Fenton English, 1819–1869

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Villa Pamphili outside Porta S. Pancrazio, from Views of Rome

Giovanni Battista Piranesi (Italian, 1720-1778) published by Francesco (Italian, 1758-1810) and Pietro Piranesi (Italian, born 1758/9)

0% similarityCheck object rights; API metadata is openArt Institute of Chicago

Portrait of a Man with Gray Hair

Henry Raeburn (Scottish, 1756–1823)

0% similarityCheck object rights; API metadata is open

Comparable logic

Specialist model explanation

Comparable IDMatchPriceReasons
2221953%602.0 SEKidentity 59%, material 45%, size 62%, title 55%, hallmarks 45%, weight 62%
1428653%1120.0 SEKidentity 59%, material 45%, size 62%, title 57%, hallmarks 45%, weight 62%
983253%16600.0 SEKidentity 59%, material 45%, size 62%, title 53%, hallmarks 45%, weight 62%
1338753%1876.0 SEKidentity 59%, material 45%, size 62%, title 52%, hallmarks 45%, weight 62%
1333853%4200.0 SEKidentity 59%, material 45%, size 62%, title 52%, hallmarks 45%, weight 62%
1835853%1629.0 SEKidentity 59%, material 45%, size 62%, title 49%, hallmarks 45%, weight 62%
998953%10777.0 SEKidentity 59%, material 45%, size 62%, title 51%, hallmarks 45%, weight 62%
960053%60000.0 SEKidentity 59%, material 45%, size 62%, title 51%, hallmarks 45%, weight 62%

Automatic signature module

Every artwork image is checked for signatures and marks

The local engine detects and isolates candidate regions, searches the trusted mark library and runs conservative signature forensics. Optional AI interprets unreadable regions and creates research queries without changing the forensic verdict.

Candidate regions0
Signature regions0
AI enrichmentLocal only
PipelineNot run

No automatic mark result yet

The module runs during normal analysis when a local image is available.

Marks laboratory

Isolate and identify signatures, hallmarks and maker marks

110 independent methods generate cleanup variants, stroke and symbol descriptors, library matches, trust controls and conflict warnings.

Open mark library

Match an unknown mark

Upload the tightest available crop. Include a little surrounding surface so the system can separate paint, engraving, glare and background.

Add a known reference

Signature forensics

Check consistency with known genuine variation

This does not declare a signature genuine. It measures fit against a multi-source reference set, confusing signers and natural variation.

No forensic check yet

Run mark matching first, then compare the questioned signature against a sufficiently broad trusted reference set.

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