An investigation of paint from a mural in the church of Sainte Madeleine, Manas, France
Bibliographic record
Abstract
The pigment in brown paint samples taken from a church in the Drôme region of France has been shown to be almost pure 6-bromoindigo and 6,6'-dibromoindigo. The composition of the pigment was established by comparison with 6-bromoindigo and 6,6'-dibromoindigo standards using atmospheric pressure photoionization combined with liquid chromatography and tandem mass spectrometry. The brown paint samples were taken from a frieze of ca 20 brown images having symmetric tree-like forms composed of five overlapping filled circles representing foliage. The tree-like images, simple rather than artistic, had a metallic luster. The molar ratio of 6-bromoindigo and 6,6'-dibromoindigo in the brown paint pigment (98:2) is remarkably similar to that of shellfish purple from the Mediterranean Murex brandaris (96.5:3.5) thus, it is possible that the origin of the indigoid compounds in the brown paint pigment is the eastern coast of the Mediterranean Sea. As the production of Tyrian purple ended with the fall of Byzantium in 1453, purple pigment had to have been produced prior to this time. We have conjectured about the circumstances that may account for the use of 'purple' in this manner in the Drôme region and how the pigment was transported there from the eastern coast of the Mediterranean Sea during the time of the Crusades.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".