Phone 800-987-8129
Fisher Forensic Document Laboratroy Inc.

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Forensics Lab located in San Ramon, CA

2010 Crow Canyon Place Suite 100
San Ramon, CA 94583

Ms. Fisher provided excellent analysis in a very difficult and complex matter requiring the evaluation of many important amendments to a trust document...

Services / laboratory

Fisher forensic document laboratory offers a state of the art facility for non-destructive testing. With over 30 years experience, M. Patricia Fisher provides critical analysis of testing results to determine inconsistencies and illuminate suspect details of questioned documents. Qualified to testify in over 245 trials, presentation may encompass oral presentations, written reports with illustrative exhibits, and testimony with exhibits. When necessary additional team specialists in microscopy and macro photography may be utilized.



Using state-of-the-art equipment can make a difference in accurately testing and analyzing evidence. Microscopic examinations permit the examiner to see fine details in handwriting and in other evidence.

Testing Example

Yellow dots seen near the letters "redit," not readily seen with the naked eye, identify the printer as a color laser.  These dots can also be recorded with a UV source.  This case questioned whether the documents were from the same source. 

Arrows point to four dots that are similarly placed on both documents.

Comparing the placement of the scattered yellow dots in the upper left image to the UV image of a second "redit" below provides strong evidence, along with other document evidence, that the two documents were probably printed on the same color laser printer.

The pattern of dots may even assist law enforcement in tracking down a specific printer used to create counterfeit money. 



Evidence, once examined and recorded, must be analyzed to elucidate the results of the testing.

Analysis Example

Image (left) from an original document containing at least three different writing instruments along with white-out, and an orange marker. Using an infrared source (right) confirms the two black writing instruments are different. Liquid based black ink shows luminescence (a glowing effect) with an infrared source and additional "spot" lights. This black ball point pen does not show luminescence.

The dollar sign, the overwriting of the "I" and the first stroke of the "N" are written with a blue ball point pen that also shows luminescence. 

This example shows two pens that may at first appear similar. Upon further investigation, the document examiner can state with certainty the two writing instruments containing black ink are from different pens.


Analysis Example 2

Results of the indented writing lifts demonstrated that the date and the two signatures of the decedent were in contact with each of the additional pages of the will.  An example of the indentations of the two signatures and date from page 2 of the will are seen in the indented writing lift below. These indentations tell the examiner that all pages of the will were in contact with each other when it was signed and dated.



Presenting evidence that has been tested and analyzed is the next critical step.

Enlarged microscopic images can often clearly demonstrate whether a writing is naturally executed or contains common indicia of being simulated or copied from a model or models.

Presentation Example

Comparing an original questioned year 10 to a known year 10 dated approximately two weeks apart. Here the questioned 10 shows a slower, uncertain movement. These changes of direction within the lines or curves are what document examiners call poor line quality. 

The known contemporaneous sample is written quickly and fluently without the slower execution and poor line quality seen in the questioned year 10.


Team Specialists

Capturing images of questioned documents requires specialized microscopes combining the best optics with the newest digital cameras. Working with Patricia Fisher, Mr. Rosenthal and Mr Barabe provide invaluable assistance in resolving specialized issues in forensic document examination.

Keith Rosenthal

Evidence photographer at Rosenthal Forensics, Napa, CA

Certified evidence photographer with more than 50 years of professional photography experience. Mr. Rosenthal has been qualified in Federal Court as an expert in forensic photography and lighting. Mr. Rosenthal utilizes the most appropriate microscope from his collection of 10 Carl Zeiss microscopes. He brings an understanding of the technology he uses as well as the currently accepted standard operating procedures and methodologies required for examining questioned documents. Mr. Rosenthal also uses ultra violet and infrared sources as one of the powerful tools which allows the team to discover and scientifically record evidence not readily visible to the naked eye. Working with Patricia Fisher, Mr. Rosenthal provides invaluable assistance in resolving specialized issues in forensic document examination. For example, he recently assisted Ms. Fisher with a sequencing of inks lines question that required co-axial lighting at higher magnifications. In addition, with his wide range of microscopes along with his extensive experience in photography and lighting, Mr. Rosenthal assists with document problems that may require precise measurements of lines, angles, hole-punches, paper imperfections, and other aspects of the documents as needed.

Joseph G. Barabe

Senior Research Microscopist at Barabe & Associates LLC, Oak Park, IL

Specializes in materials analysis of art, historical objects and documents, from ancient to contemporary. He studied microscopy under Dr. Walter McCrone, and recently retired from McCrone Associates Inc. in Westmont, IL. His special interests include printing process identification (historical and contemporary, fine art, commercial and office) and altered and forged documents, exclusive of handwriting identification issues, and the identification of printing inks and paints, especially when the date of composition of the document or item is in question. He teaches workshops in Microscopy for Forensic Document Examiners, which covers the basic theory and use of the stereomicroscope, including micrometry, a history of ink, writing instrument identification, Printing Process Identification, and the Microscopical Identification of Art Pigments at the Hooke College of Applied Sciences in Westmont, IL, or on site. He frequently contributes oral presentations at professional forensic document examiners' and art conservation symposia, and he has published frequently in the Journal of Forensic Document Examination on topics including sequence of writing, ink analysis and printing process identification. Notable publications relevant to forensic document examination include "Printing Process Identification: A Microscopical Atlas," (2010, Vol. 20, pp 5 – 37), and, with M. Patricia Fisher and Walter Rantanen, "RARE 1972 Marilyn Monroe Oyama Photo Book," (2007 Vol. 18 pp. 41 – 62), a case study of a fabricated collectible publication.


Need help? 30 Years Experience available as your resource

Ms. Fisher has developed a broad background in the examination of hundreds of thousands of documents in over 3000 cases and has testified in over 245 trials in state and federal courts, in addition to providing testimony for arbitrations, hearings, and depositions.


Video-Conference facilities on site



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