Paper examinations usually become necessary when there is some question as to whether one or more pages have been added to a multi-page document, or if a document was created at the time that it purports to have been created. As an example, a Last Will or contract may be such a document. There may be suspicion that one or more pages have been added or replaced subsequent to the original execution of the document.
Without going into great and unnecessary discussion of the paper manufacturing process, paper is commonly made of wood and/or cotton materials. During the production, various sizings, fillers, and coatings are added. Sizings, such as rosin, enable the paper to resist ink penetration. Fillers, such as clay, calcium carbonate, and titanium dioxide improve the surface and color of the paper. Various coatings are added to the paper to improve the appearance and printing properties. These additives will vary from one paper type or paper manufacturer to another.
Chemical testing can determine which of these materials are present, and even the type of wood that was used in the paper’s manufacture. A comparison of the results of such testing can associate or dissociate a questioned page with the remainder of the document. Unfortunately, these chemical processes are destructive in nature and require sampling of both the questioned page and the other remaining pages. This is most often not convenient, allowed by the courts, the opposition, or the owner of the document. There are, however, many other properties of the paper that can be investigated and compared without damage to the document.
Paper Size and Thickness
While there are standard sizes for paper, such as “letter” (8½” x 11″), or “legal” (8½” x 14″), very small differences in lengths and widths exist between different manufacturers and even between different papers in a specific manufacturer’s paper line, or even between different “runs” of the same paper. While these small differences can be measured, the simple process of stacking the questioned and standard paper will normally display even small differences in size.
As in paper size, various but minute differences in thickness can be detectable. This determination will require instrumentation, however. A paper micrometer is the weapon of choice. Most micrometers will display differences in thousandths of an inch.
Paper Opacity, Color, & Brightness
Papers opacity, color, and brightness are directly related to the chemical additives that were put into the paper during its manufacture. Differences between two papers in these areas may, at times, be easily observed with the naked eve. When held up to a light source, one paper may transmit more light through it than another. Obvious differences in color or shading between papers can likewise be an unaided observation. While paper brightness may also fall under the unaided eye category, often two similar-appearing (brightness) papers will display patent differences when subjected to a short-wave and/or long-wave ultraviolet light source. While one paper may remain dull in appearance, the other may almost glow.
Some paper when held up to the light display an area of translucent design, the watermark. This design is incorporated into the paper by one of several different methods during the paper manufacturing process. A discussion and description of these various methods would be much to long for this short section and would necessarily have to be preceded by an even lengthier discussion of the paper manufacturing process itself. What is important is for the reader to know that most often these designs contain manufacturer and paper content information in addition to “hidden” clues regarding the first date of that paper’s production. For example, a questioned document that purports to have been executed in 2001 may contain a watermark that, after research, proves that the paper was not made until 2012.