As forgers differ in their capability as to accuracy in simulation, all grades of its proficiency come up in the experience of those who, as experts, are called upon to make such matters a study.  At one extreme will be found to occur signatures written with but little effort to imitate the genuine signature they purport to represent; with all the intermediate grades of imitation extending to the other extreme, wherein a skilful forger will, by practice, so simulate the signature of a person and with such close resemblance that the very individual whose name is imitated cannot, independently of attending circumstances, tell the forgery from the signature which he knows he has written.

Among the most common forgeries of signatures are those which have been traced from genuine ones, and these are produced in various ways; the most common method being to place the genuine signature over a plate of glass horizontally arranged, with a strong light behind it, or against the window frame, and then to place over the signature so positioned the paper on which the forgery is to be made.  When this has been done the papers are held in contact firmly, the pen is dipped-in ink and moved over the paper, guided by the lines of the genuine signature beneath, which show through the superimposed paper, and by means of which the form of the signature is transferred to the paper, which is exteriorly placed.

While the process of tracing produces very nearly the proper form of the matter thus copied, and if well done by the forger the copy will in general appearance and to a certain extent resemble in outline the signature thus traced, there are usually apparent in all reproduced signatures thus made, peculiarities and ear marks indicating the manner in which they were produced and by which they can be identified as such.

One of the most prominent features of reproduced signatures is the general sameness of the writing as appearing in the uniform width of the lines, and the omission of the usual shading emphasis.  The cause of this appearance is the absence of habitual pen pressure, and the necessitated slow movement of the pen held closely in contact with the paper and by which a uniform and steady flow of ink is deposited thereon; thus making what should be the heavier and lighter lines of one width and density as to shading.  This method of tracing and reproducing signatures is that usually resorted to by novices but is seldom employed by expert forgers.

Another condition appearing in all traced signatures is the absence of all evidence of pen pressure when examined as a transparency; this deficiency occurring as consequent upon the manner of moving the pen over the paper.  While signatures thus made may resemble the one from which they are copied, the only likeness they have is that of pictorial resemblance and it will be found to be destitute of all the appearances and indications of habitual writing in other respects.