Subject-matter can only be regarded as having been made available to the public, and therefore as comprised in the state of the art pursuant to Art. 54(1), if the information given to the skilled person is sufficient to enable him, at the relevant date (see G-VI, 3), to practise the technical teaching which is the subject of the disclosure, taking into account also the general knowledge at that time in the field to be expected of him (see T 26/85, T 206/83 and T 491/99).
Where a prior art document discloses subject-matter which is relevant to the novelty and/or inventive step of the claimed invention, the disclosure of that document must be such that the skilled person can reproduce that subject-matter using common general knowledge (see G-VII, 3.1). Subject-matter does not necessarily belong to the common general knowledge simply because it has been disclosed in the state of the art: in particular, if the information can only be obtained after a comprehensive search, it cannot be considered to belong to the common general knowledge and cannot be used to complete the disclosure (see T 206/83).
For example, a document discloses a chemical compound (identified by name or by structural formula), indicating that the compound may be produced by a process defined in the document itself. The document, however, does not indicate how to obtain the starting materials and/or reagents used in the process. If the skilled person moreover cannot obtain these starting materials or reagents on the basis of common general knowledge (e.g. from text books), the document is insufficiently disclosed with respect to that compound. Hence, it is not considered to belong to the state of the art according to Art. 54(2) (at least in as far as it relates to that compound) and consequently it does not prejudice the patentability of the claimed invention.
If, on the other hand, the skilled person knows how to obtain the starting materials and reagents (e.g. they are commercially available, or are well-known and appear in reference text books), the document is sufficiently disclosed with respect to the compound and therefore belongs to the state of the art according to Art. 54(2). The examiner can then validly rely upon this document to raise objections against the claimed invention.