caput mortuum
Enable an agent to identify material called caput mortuum, distinguish historical residue terminology from pigment usage, and assess a particular sample for a proposed use.
Bundle → Layer → Finding → Questions Filled
5 bundles · 9 layers · 13 findings · 21 questions
Name and material identity Establish what caput mortuum denotes in the registry and in each material record.
Attested meaning
Separate documentary meanings before assigning properties.
Historical residue sense
Historical chemistry used the term for material remaining after volatile substances escaped; this denotes a relationship to an operation rather than a fixed composition. [Historical dictionary entry](https://en.wikisource.org/wiki/The_New_International_Encyclop%C3%A6dia/Caput_Mortuum).
- Does the registry's originating record identify a residue, a pigment or another sense? definition
- Which passage or label establishes the intended meaning for this sample? provenance
Pigment name boundary
Test the pigment interpretation without collapsing related colour names.
Documented pigment sense
CAMEO describes caput mortuum as a historical reddish-brown iron-oxide pigment name and lists several related terms; a sample's equivalence to any of those terms still requires evidence. [CAMEO material entry](https://cameo.mfa.org/wiki/Caput_mortuum).
- What evidence supports interpreting this record as a pigment material? definition
- Does a proposed synonym identify the same material, a related pigment or merely a similar shade? boundary
Origin and composition Connect a named material to its preparation history and analytical identity.
Formation history
Record the operations and feedstocks actually supported by evidence.
Documented preparation
Keep reported preparation routes distinct from routes inferred from the name or appearance.
- Which feedstock and operation produced this particular residue or pigment? provenance
- Was it subsequently washed, heated, ground or blended, and where is that recorded? provenance
Analytical identity
Identify constituents and phases independently of the caput mortuum label.
Composition before identifiers
Assign chemical identifiers only to evidenced constituents; retain uncertainty for uncharacterised mixtures.
- Which constituents and mineral phases have been measured, by what methods and with what detection limits? measurement
- Does each proposed identifier describe a constituent, the whole material or a formulated product? boundary
Pigment appearance and performance Assess optical and working properties when pigment identity is supported.
Shade comparison
Compare colour under controlled viewing and preparation conditions.
Reproducible colour
Record shade as an observation of a prepared sample rather than an invariant implied by its name.
- What colour coordinates and spectral measurements describe the powder and a standardised drawdown? measurement
- Which reference sample and tolerance define an acceptable caput mortuum shade for the intended application? action
Binder and aging response
Establish application performance through sample-specific evidence.
Tested application behaviour
Record dispersion, opacity and colour retention in the intended medium; do not transfer results between undocumented formulations.
- How do particle size and preparation affect dispersion and opacity in the chosen binder? measurement
- What testing supports acceptable colour retention under the intended light, heat and environmental exposure? action
Sample condition and use decisions Translate the condition and evidence for a specific material into bounded decisions.
Sample integrity
Check whether the material tested represents the material to be used.
Representative material
Record heterogeneity, contamination and changes since collection or manufacture before relying on an analysis.
- Does the sample contain visibly distinct fractions, added binder or contamination? measurement
- Which sampling and storage records support treating the analysis as representative of the current material? provenance
Evidence-bounded use
Associate proposed handling and applications with evidence for the actual sample or grade.
Use-specific assessment
Keep handling requirements, supplier classifications and application acceptance tied to the documented composition and physical form.
- Which current sample or product documentation establishes applicable handling constraints for the proposed operation? action
- What unresolved identity, impurity or performance evidence prevents accepting this material for the stated use? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these check these first hold for the sense of caput mortuum this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these identifiers and schemes hold for the sense of caput mortuum this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these real-world use hold for the sense of caput mortuum this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these failure modes and hazards hold for the sense of caput mortuum this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of caput mortuum this model covers, and on what evidence? provenance
Classifiers Filled
- Family
- Thing Registry
- Category
- Physical world and living systems
- Entry kind
- thing
- Plane
- PHY
- Domain
- PHY.MAT
What it is Filled
Caput mortuum is a traditional name for a muted violet-brown iron-oxide pigment, principally associated with hematite, and historically also designated the residue left after certain alchemical operations.
In scope
- Evidence establishing which material sense of caput mortuum applies
- Historical or commercial provenance of a named sample
- Measured constituents, phases, impurities and physical form
- Colour and application properties when the material is a pigment
- Sample-specific handling constraints and fitness for a stated use
Out of scope
- Alchemy as a symbolic or philosophical system
- The distillation, sublimation or calcination process as an independently modelled activity
- Finished paint formulations and artworks containing the material
- Iron oxides generally, beyond their evidenced relationship to a sample
- Colour names or digital colour coordinates without a material referent
Why it exists Filled
Enable an agent to identify material called caput mortuum, distinguish historical residue terminology from pigment usage, and assess a particular sample for a proposed use.
Distinguishing features Filled
- Require contextual evidence: a residue named in a historical operation and an artist's pigment carrying the same name are not automatically compositionally equivalent.
- For pigment usage, compare both composition and measured colour; a reddish-brown appearance alone does not establish caput mortuum identity.
- Distinguish a pigment powder from a binder-containing paint sold under the same colour name.
- Treat related names such as colcothar or Venetian red as candidate relationships requiring evidence, rather than universal interchangeable identities.
- Do not infer human-derived material from the literal meaning of the name or an association with mummy brown.
What robots and AI may and may not do Filled
Must not
- Present the name as proof of a particular composition without analysis.
- Use pigment dust without dust control where people breathe it.
- Misattribute an artwork based on pigment alone.
Only with a human decision
- Conservation treatment of an artwork using it.
May
- Identify the pigment by name, colour and its iron oxide composition, citing sources.
- Distinguish the pigment sense from the alchemical sense of residue.
- Report its use in historical artworks from conservation records.
Moral aspects Filled
- Pigment analysis supports attributions that affect artists' legacies and value.
Who is affected
- Artists and conservators
- Owners of artworks
Owners Filled
Steward
Nobody owns the pigment; owners of artworks answer for works that use it.
Links to other meta-models Filled
parent
- Q161179 - registry parent class
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.caput-mortuum
- Wikidata: Q421089 (https://www.wikidata.org/wiki/Q421089)
Direct properties required Filled
- Attested material sense: historical process residue | pigment material | unresolved
- Identity evidence: Links to registry origin, historical passage, collection record, supplier documentation or analysis
- Constituent and phase composition: Constituent mass fractions in wt%; phase identifications with method and uncertainty
- Chemical and pigment identifiers: Documented CAS, EC or Colour Index identifiers, each attached to its actual constituent or product
- Physical form and condition: powder | agglomerated powder | coherent residue | dispersion; moisture and contamination observations
- Particle-size distribution: µm; distribution basis, dispersion method and agglomeration state
- Measured pigment colour: CIELAB coordinates with illuminant, observer, binder, substrate and film preparation
- Process ancestry: Documented feedstock, operation, date and treatment history; unknown where unavailable
- Use assessment: untested | supported for specified use | unsuitable for specified use | evidence insufficient
Recognition required Filled
- Muted violet-brown or purplish iron oxide powder or paint.
- Analysis confirms hematite as the principal component.
Capabilities and actions required Filled
- Disambiguate a caput mortuum label using its documentary and material context.
- Compare a sample with a documented pigment reference using composition and controlled colour measurements.
- Plan analyses that distinguish an iron-oxide pigment from another process residue.
- Evaluate pigment dispersion and appearance in a specified binder through documented trials.
- Determine whether evidence supports handling or application under specified conditions.
- Preserve unresolved identity claims without merging chemically different samples.
Hazards and failure modes required Filled
- Fine dust can irritate the lungs when handled dry.
- Name confusion between suppliers leads to mismatched colours in restoration.
Standards and interfaces required Filled
- The European Union REACH Regulation applies to pigment substances manufactured, imported or supplied within its scope, including iron-oxide pigments.
- The European Union Classification, Labelling and Packaging Regulation governs hazard classification and labeling of pigment substances and mixtures supplied within its scope.
Context of use required Filled
- Caput mortuum is encountered in artists' pigments, historical paintings and conservation studies as a muted violet-brown iron-oxide colorant.
- In alchemical texts, the same name can refer to residual material after an operation, so its meaning must be established from the historical context.
- A historical residue cannot be assumed to have the composition or suitability of a modern pigment sold under this name.
Sources Filled
- Wikidata item Q421089: caput mortuum - identity and sense of the item
- Wikipedia: Caput mortuum - general description of the item
Open questions
- Does the registry's originating entry intend the historical chemical residue, the pigment or both?
- Does an existing world model already own the intended concept, requiring this entry to link to it?
- Which historically and commercially documented compositions fall under this name, and which related pigment names are equivalent only in particular contexts?
- Which analytical identifiers, impurity limits and handling classifications can be established for the actual material or grade?
- Which reference specimens and test conditions should anchor colour, dispersion and durability comparisons?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q421089/spec.json