D – Glossary Terms

Decoration (ceramics/ glass):

Gilding, glaze, enamel, paint, slip or unfired decoration often found on ceramic or glass objects.

Deformed / Distorted / Misshapen:

Changes in shape and form, detracting from objects original appearance.


When objects are weakened or has a loss of tensile strength. Degradation can lead to objects becoming fragile and running the risk of incurring further damage or loss.

Delamination (organics):

Separation of layers, may refer to separating of layers joined in construction of the object, may be between layers of same or different materials, or separation within a laminar material, e.g. Shell, mica.

Delamination (Paper):

Linings separating out from one another, usually leaving bubbles where voids are present between layers. This is also referred to as splitting.

Delaminating / Lifting (ceramics, glass, metals):

Separation between layers of the original material in which pieces are partially detached or raised. E.g. paint


Hollows or depressions in the surface of the object, often caused by pressure or an impact.

Deteriorated (ceramics/ glass):

Object in poor condition which may include; weathered glaze, deteriorating adhesives, flaking or lifting glaze, unstable gilding, unfired decoration, loose surface material, cracks.

Deteriorated (metals):

General term to denote poor condition of the object material.

Deterioration (processes of):

All materials follow certain deterioration patterns and processes. By identifying materials it helps conservators to predict and inhibit these processes.


A deposit of dirt, dust, grime or other contaminant absorbed into the surface and not easily brushed off.


An overall change in the colour of a material, usually to a darker, more yellow or brown appearance. This may be caused by light damage or by exposure to acidic substances.

Discolouration / yellowing / fading / darkening:

Permanent change in the colour of the material due to light damage or chemical change, may be overall, may be localised, often can see difference between where material is exposed to light and where covered.


A deposit of dirt, dust, grime or other contaminant absorbed into the surface and not easily brushed off.


Quite often conservators would take an object apart and put it back together in order to conserve it.


Shape is changed from its original, natural or intended form.

Dowelling / Joining:

A dowel is a small round wooden peg that is used to strengthen or reinforce a joint – often in organic objects.


Particulate material which has settled on the surface of the object and contributes to corrosion, staining and abrasion.


Loose dust and dirt lying on the surface, can be brushed off relatively easily.

Dye transfer /bleeding / crocking:

Spread of dye colour from coloured to uncoloured area – bleeding due to water, crocking due to excess dye rubbing off through friction.