Shipman Colour Stages
Definition
The five-stage colour classification (yellow-tan, brown, black, blue-grey, white) published by Patricia Shipman and colleagues in 1984, corresponding approximately to temperature ranges from below 200°C to above 700°C.
- Authors
- Patricia Shipman and colleagues, published 1984
- Stage sequence
- Yellow-tan, brown, black, blue-grey, white
- Approximate range
- Below 200C through above 700C
- Basis
- Progressive loss of organic collagen and change in bone mineral structure with heat
Common questions
Why does bone change colour through these stages instead of just charring uniformly?+
Each colour reflects a different chemical process: yellow-tan and brown mark early scorching and collagen breakdown, black marks carbonisation of remaining organics, and blue-grey through white mark progressive oxidation of the mineral component as the last carbon burns off, leaving essentially inorganic calcined bone.
Can the Shipman stages be used to read an exact temperature the bone reached?+
Only approximately. The stages give a temperature range, not a precise value, because duration of heating, oxygen availability, and the specific skeletal element all shift where a given colour appears, so the scheme is used alongside other evidence rather than as a standalone thermometer.
Related terms
- Calcined Bone
- Bone heated to above approximately 700°C, resulting in complete combustion of the organic component (collagen), leaving only mineral hydroxyapatite; characterised by white...
- Crazing
- A mosaic network of intersecting surface fissures on burned bone, produced by differential contraction of the outer bone surface relative to the...
- Delamination
- The separation of the outer table of bone from the underlying diploe or cortex in curved sheets during green-bone burning; produced by...
- Dry Bone Fracture Pattern
- Straight, longitudinal fractures running parallel to the long axis of a bone, following the Haversian structural directions; characteristic of bone burned after...
- Green Bone Fracture Pattern
- Curved transverse fractures running approximately perpendicular to the long axis of a bone, with a stepped or warped cross-sectional profile; characteristic of...
- Hydroxyapatite (HA)
- The calcium phosphate mineral [Ca10(PO4)6(OH)2] that comprises approximately 70 per cent of bone mass; survives fire at all temperature stages, sintering and...
- NFPA 921
- US National Fire Protection Association Guide for Fire and Explosion Investigations. The internationally accepted methodology Indian fire investigators and SFSL fire divisions...
- Pope-Smith Framework
- The 2004 analytical framework distinguishing perimortem from postmortem fire exposure using fracture geometry, cross-section colour uniformity, periosteal behaviour, and anatomical integrity; explicitly...
- ZooMS (Zooarchaeology by Mass Spectrometry)
- A peptide mass fingerprinting method using collagen fragment masses to identify bone to species level; applicable to burned bone samples where conventional...