Hilton, Ordway

English

Northwestern University Illinois, School of Law: Scholarly Commons

Journal of Criminal Law and CriminologyVolume 40 | Issue 4 Article 111950Pitfalls in the Use of Ultraviolet Examinations toDifferentiate between Writing PapersOrdway HiltonFollow this and additional works at: https://scholarlycommons.law.northwestern.edu/jclcPart of the Criminal Law Commons, Criminology Commons, and the Criminology and CriminalJustice CommonsThis Criminology is brought to you for free and open access by Northwestern University School of Law Scholarly Commons. It has been accepted forinclusion in Journal of Criminal Law and Criminology by an authorized editor of Northwestern University School of Law Scholarly Commons.Recommended CitationOrdway Hilton, Pitfalls in the Use of Ultraviolet Examinations to Differentiate between Writing Papers, 40 J. Crim. L. & Criminology519 (1949-1950)PITFALLS IN THE USE OF ULTRAVIOLETEXAMINATIONS TO DIFFERENTIATEBETWEEN WRITING PAPERSOrdway HiltonThe author is an Examiner of Questioned Documents, New York City. Prior toundertaking work as a private .consultant he served first as document examiner onthe staff of the Chicago Police Scientific Crime Detection Laboratory and thenduring the war as a handwriting identification specialist with the Naval IntelligenceService. Mr. Hilton is a member of the American Society of Questioned Docu-ment Examiners, an organization which numbers among its membership the leadingdocument examiners in this country, Latin America, and Great Britain. In additionto having served on the Editorial Board of this Journal and as its Editor, he hascontributed several papers to this and other legal publications.-MANAGING DMECTOR.Examination under ultraviolet radiation has been recognizedfor some years as a means of differentiating* between writingpapers made of different kinds of fibers.1 Chemical wood pulppaper, for example, fluoresces differently than cotton rag paper,and examiners of questioned documents have rather generallylooked upon variations in color and quality of fluorescencebetween two specimens of paper as indicating a difference incomposition and therefore a different source or time of manu-facture. In a document of several pages, if one page fluorescesunlike the remainder, this fact has been accepted by some work-ers as an indication that the page had been substituted. Theaccuracy and reliability of this test has been investigated experi-mentally and is reported upon in this paper.Investigation into this problem was prompted by questionsraised at the 1948 meeting of the American Society of Ques-tioned Document Examiners. A major portion of this annualmeeting was devoted to the discussion and investigation of writ-ing paper identification problems. The sessions were held inAppleton, Wisconsin, where members of the Society and keypersonnel on the staff of the Institute of Paper Chemistry con-ducted a joint seminar on methods of paper identification. TheSociety members also made a special inspection tour of twowriting paper'mills in that city.2 One of'the questions -discussedat the seminar was the reliability of ultraviolet fluorescence asa means of differentiating between sheets of writing papers.Staff members of the Institute of Paper Chemistry pointed outthe limitations encountered in their investigation of the subject.Furthermore, certain trade practices observed at the papermills also suggested that the accuracy of .ultraviolet tests might1 See Elbridge W. Stein, "Ultra-Violet Ligh and Forgery", Scientific American,.147(4) :204-6 (Oct. 1932).2 The mills visited were the Fox River Paper Corp. and the Riverside Paper Co.ORDWAY HILTONnot have been investigated far enough. The entire discussionraised one basic question which had not been satisfactorilyanswered: Could a difference in ultraviolet fluorescence betweentwo sheets of the same brand of paper necessarily mean thatthey did not come out of the same box?MILL AND TRADE PRACTICESIn attempting to answer this question the methods of manu-facture and distribution of writing paper become import~ant.The manufacturing process itself is the obvious starting point.It is assumed that the reader is familiar with the Fourdriniermachine and its operation. This is the machine which is used inthis country to make most writing papers. After the paper webcomes off the dry end of the Fourdrinier machine it is wound ona reel in a large continuous roll. These rolls are made up of arun of one to one and one-quarter hours of paper making, de-pending on the particular mill and consequently contain thou-sands of -feet of paper.3Before the writing paper is shipped from the mill it may becut into large sheets and packaged into ream units. The widerolls which are taken off the paper machine are generally cutinto narrower widths in a rewinding process before sheeting. Acommon type of sheeting machine in use today can be fed fromas many as ten rolls of paper simultaneously, cutting the paperinto the individual sheets and stacking them. Counting is doneby .an employee who operates the machine. With a machine ofthis kind feeding ten rolls at once, -it may be that only everytenth sheet comes from the same machine run.When these large sheets are packaged, they are shipped tostationery firms who cut them into the common commercialsheets, such as letter and legal size, and box or repackage them.These are the packages and boxes sold by the retailer. Withoutany mixing of lots during this last operation-a rather unlikelyhappening with the type of cutters used-the sheets of paperthat are found in a retail box may well represent an assortmentfrom as many as 10 different mill runs.The entire question now resolves itself into how. uniform thepaper composition is held during ten consecutive machine runs.Interrogation of mill supe.rintendents and chemists at the plantsreveals that the person supervising the run determines the com-position of stock within certain limits. Corrections may be made3 The usual speed of paper making in a writing paper mill is from 300-500 feetper minute.[Vol. 40PITFALLS IN ULTEAVIOLET EXAMINATIONSFigure 1.Four sheets of Engraver's Parchment writing paper were photographed Underultraviolet radiation. The sheets are arranged in the order in which they weredrawn from the box. Not only is there a difference in the intensity of fluorescence,but there is also a variation in color. Samples A and C showed blue-grey in tint;B and D, purplish. (Enlargement 2X. Corning 986 filter ov er mercury vapor lampsource. No filter over camera lens.)from time to time in color, bleach, brightness, loading materials,sizing, and the like. These decisions are based upon his experi-ence and the appearance of the paper as it comes off themachine. In the 10 to 12 hours necessary to make the paper atleast two shifts would have handled the various runs. Overthis period of time it is always likely that slight changes incomposition may be made. Thus, all sheets in a retail box neednot have been made absolutely identical, and, consequently,their fluorescent qualities may be affected.EXPERIMENTIn order to test the reliability of ultraviolet fluorescence asa means of differentiating between two sheets of the samebrand of paper, and especially to check on the uniformity ofthe fluorescent quality of successive sheets from the same box,a series of tests were made on different brands of rag contentwriting paper.4 15 consecutive sheets were taken at randomfrom the box, and successive sheets were compared under ultra-violet radiation. A Corex 986 ultraviolet filter was used overthe mercury vapor generator to eliminate the visible light.Examination was made visually in order to duplicate the exactconditions under which the preliminary ultraviolet inspectionof disputed papers are made.With two brands the quality of fluorescence was not the samefor all sheets, although the majority of papers tested showed4 Papers tested were: Ebac Linen Bond (John McCabe & Co., N. Y. C.) ; SpencerBond; Strathmore Parchment, 100% rag content (Strathmore Paper Co., W.Springfield, Mass.) ; Old Treaty Bond (W. C. Hamilton & Sons, Inc., Miquon,Pa.); and Engraver's Parchment (Southern Paper Co., Inc., Birmingham, Ala.).1949]ORDWAY HILTON[no appreciable variation in fluorescence between successivesieets.The most pronounced difference between sheets was foundii, Engraver's Parchment letterhead paper. Not only did theintensity of fluorescence vary from sheet to sheet but also thecolor. Some sheets showed a characteristic purplish fluorescencewhen subjected to ultraviolet rays while others appeared lighterand more nearly grey-blue in color, In all the. differences wereconclusive. A second sample from another box of the samepaper, purchased at the same time as the first, substantihtedthese findings. After this preliminary visual inspe.ction an ultra-violet photograph was made and is reproduced in Figure 1.The results of tests on Spencer Bond were less pronounced,but still significant. All sheets fluoresced the same color, but.there was a gradation in the intensity, some being darker thanothers. This difference seemed somewhat more in keeping withslight changes that might be made in the course of several millruns. No attempt was made to record the difference photograph-ically.CONCLUSIONSFrom this investigation it would appear that trade practicesin the writing paper industry can bring about packaging ofconsecutive sheets of paper from different mill runs. Someruns may produce paper which show different fluorescent quali-ties from other runs in the same package. -In the brands ex-amined this condition was found in two instances, but it was nottrue with all papers tested. It would seem reasonable to con-clude therefore that a marked difference in fluorescent qualitiesof two questioned sheets need not necessarily mean that onenust have been substitued in the document subsequent to itspreparation. Unless it can be shown from a 'epresentativesample of paper from the supply in use when the document wasprepared, or there is other evidence to substantiate a conclusionof substitution, it is entirely possible that the two sheetsoriginated in consecutive order in the same box. In the lightof this investigation conclusions drawn from differences inultraviolet fluorescence of writing paper must be interpretedwith caution.[Vol. 40

Pitfalls in the Use of Ultraviolet Examinations to Differentiate between Writing Papers

https://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=3709&amp;context=jclc

Pitfalls in the Use of Ultraviolet Examinations to Differentiate between Writing Papers

Abstract

Similar works

Full text

Available Versions

Northwestern University Illinois, School of Law: Scholarly Commons