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It may be possible to answer the question of whether or not a document was signed in blank, or after typing, by a microscopic examination of the line intersections. By removing the typewriter carbon at the point of the intersection, it can be clearly seen whether there is ink under the carbon or if the ink was removed with the carbon. A technique for determining the sequence of typewriting and most types of inked entries was developed. The results may be recorded photographically and subsequently used as a demonstrative exhibit in presenting the evidence during trial.

Documents containing indentations from other written papers may also contain original written material on the reverse side of the page. When such a document is processed on an Electrostatic Detection Apparatus (ESDA), both the subject indentations and the writing on the reverse of the paper are often recorded. It is usually very difficult to decipher the indented writing because of the overlapping images from the reverse of the paper. It is possible, however, to subtract these interfering images by making a positive transparency of the original writing on the reverse of the paper and sandwiching it with a negative of the ESDA. This method provides a clear and accurate record of the subject indentations alone.