Assertion: gallic acid | /r/CapableOf | reveal the latent image
Facets:
value: in an already exposed paper
type: LOCATION
Source sentences:
text: In his testimony, however, Reade upheld Talbot's originality, explaining that while he had used gallic acid for preprocessing the light-sensitive paper, Talbot was the first to discover that gallic acid can reveal the latent image in an already exposed paper, i.e. he was the first to develop a photographic material.