Assertion: ink | /r/MadeOf | visible
Facets:
value: by several methods
type: MANNER
value: by viewing under ultraviolet light
type: MANNER
Source sentences:
text: The ink can be later made visible by different methods according to the type of invisible ink used.
text: The ink may be revealed by heat or by application of an appropriate chemical, or it may be made visible by viewing under ultraviolet light.
text: It must be understood however that some inks - particularly those of organic origin or those consisting of a mixture of several chemicals - may be made visible by several methods.