All the examples of forgery so far mentioned are of the manufactured type, however little work may have been expended on them. In this they differ entirely from the forgeries which depend wholly on misrepresentation, a genuine article of one kind being passed off as of another, without any physical change. It is not usual to brand such things as forgeries, and legally they are not so regarded; but morally, in that something is made to appear what it is not, they seem to be truly forgeries. [Illustration: ABOVE: A forgery (partly cleaned for examination) of a fifteenth-century Florentine portrait, compared with a genuine example (BELOW). The forgery is on an old panel, but was finally proved false by the presence of titanium white, a twentieth-century pigment.] [Illustration: (genuine example)] A simple and widespread means of falsifying in this way is a certificate of authorship and genuineness. Sometimes, the writers of these are of the highest competence and probity. These two qualities are not always combined, however; and the certificate then becomes either intentionally or innocently misleading. Unfortunately, most certificates are written for a fee, and there is always temptation for the writer to err on the side of pleasing his employer; while there is no question that sometimes certificates have been given deliberately to defraud. Moreover, forged certificates bearing reputable names are not unknown, a special variety being the stringing together of words from a genuine letter, with all qualifying or negative phrases omitted. There is, however, a more insidious method of giving a certificate, that of publication of an object in a reliable journal. Editors are generally careful enough; but they are defenseless in the face of a plausible case put forward by a name of some reputation, especially when the passage relating to the object is included in a more general context. This kind of certification is particularly difficult to cope with, since such articles will continue to be cited in later publications, perhaps mainly to controvert them but nevertheless renewing their availability for dishonest purposes. Construction of false pedigrees is another means of misrepresentation, much used in the case of copies or versions. Sometimes, a pedigree is completely false, naming imaginary former owners whose existence cannot be proved but equally cannot be disproved. Sometimes, such history as the object may have is grafted onto that of another and accepted version, so that the two may become confused. A special case of this is the planting out of objects in houses whose owners are ready, for a consideration, to describe them as having descended in the family, or even as having been bought from the maker by an ancestor.