This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
620. The study of handwriting in court frequently calls for a great deal of expert testimony on either side, and is often the cause of most puzzling and contradictory statements by the various experts. And it is easy to see why this should be so, when one considers that a person's handwriting is forever varying and changing, being as much subject to the moods of the person as the weather vane is to the gusts of the wind.
In Every Handwriting Certain Distinct Features Will Continually Appear - The Dotting Of The I, The Crossing Of The T, The Peculiar Formation Of The R, Etc. but aside from these features, which sometimes only an expert in chirography can distinguish, the average handwriting will vary according to whether the writer is in a hurry or at leisure, whether in tempestuous mood or at ease with himself and the world. Is it any wonder, then, that even experts will disagree, each swearing to his own belief, or his own method of deciphering the writing in question?
622. The usual plan adopted in court, with signatures and all other handwriting, is to make enlargements, in which the various characteristics can be more clearly shown. Such enlargements should be made on transparency plates, for various reasons, more particularly because on a transparency plate an exact reproduction of the original can be procured, without elongation or stretching of the letters in any direction; whereas when paper is employed for the reproduction there is a certain amount of stretching, either in one direction or the other, often sufficient to entirely invalidate the value of the reproduction.
623. Then, again, where it is a question of comparing specimens of the same handwriting with each other, the transparency reproductions can all be brought down to the same scale, and then being mounted one on top of the other will give greater opportunities for comparison than if laid side by side, as would be necessary in the case of paper prints. The eye is easily optically deceived, and in glancing from one sheet of paper to another can easily go astray; but this is impossible, of course, where two specimens of handwriting are superimposed on transparency plates, both specimens being visible to the eye at one and the same time.
Making Negatives Of Handwriting For Enlargements. Where entire letters are to be copied for enlargements, for use as evidence, they should be reduced in size, say, one-half. This will give you accurate lines to the edge. If negatives were made the exact size of a letter, unless great care was exercised and a corrected lens employed, you would be likely to produce a slight curve in the copy, which would show slightly in the negative, yet would become quite evident in the enlargement. By making the negative a reduced size all lines can be made true, and enlargements from such negatives will be accurate.
625. When making negatives of a signature, special care must be exercised, and the signature on the negative should not be any larger than the original, and as two signatures are generally photographed - the genuine signature with that which is considered a forgery - both should be photographed from the same distance.
626. For example: After making a negative of the genuine signature, leave the camera in exactly the same position and replace the genuine signature with the forgery, placing it in exactly the same place, and then make a negative of it. In this way you will be photographing at exactly the same distance from both, and for convenience a contact transparency may be made of each, first marking each negative so as to be able to distinguish one from the other. With transparencies the original size, they may be mounted together, so that they register over each other. This method is only recommended where the forgery-appears easily perceptible.
627. For critical work, enlargements must be made from the negative, and while prints are usually made on bromide paper, yet this method is not so satisfactory as the making of enlarged transparencies. For instruction for negative and transparency enlarging, see Volume V.
628. When it is suspected that the signature is traced over another, by adjusting the two enlarged transparencies, one over the other, this will be very easily detected. If they are not copied by tracing, or if a free hand attempt at writing the name is made, then each letter must be studied carefully, and by superimposing one transparency over the other the detection can be made.