Rembrandt?: Cooperative Technical Examinations of Five Tronies by Rembrandt and his Circle
Bibliographic record
Abstract
Five tronies (character studies) painted by Rembrandt and artists in his circle, which are or have been attributed to Rembrandt, from three collections were examined using complementary technologies. Dendrochronology of the panel of Head of a Bearded Man (c.1630, Oxford, Ashmolean Museum) connects it to paintings by both Rembrandt and Jan Lievens, while infrared reflectography revealed black underdrawn lines beneath the painted surface that suggest a spontaneous creative process at an early stage. Macro-X-ray fluorescence analysis (MA-XRF) of three paintings allowed conservators at the Mauritshuis (The Hague) to identify a copper-containing pigment in the midtones of the flesh (Portrait of Rembrandt with a Gorget, c.1629), differentiate original paint from later additions in the background (Tronie of an Old Man, c.1630–31), and determine where the ground was left exposed at the surface to act as shadows of the skin (Study of an Old Man, 1650). High-resolution digital microscopy of Head of an Old Man in a Cap (c.1630, Kingston, Canada, Queen’s University) revealed the order in which layers were applied, and visualised Rembrandt’s brushstrokes, paint handling and use of a tool to scratch into the wet paint. These technologies have developed or improved significantly since the Rembrandt Research Project published their research (1982–2015), advancing our technical knowledge about the five tronies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.002 |
| Science and technology studies | 0.008 | 0.003 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.004 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".