Application of Ultraviolet Spectrum Analysis in Handwriting Test of Carbon – Free Carbon – Copy Documents

Carbon-free carbon paper, also known as pressure-sensitive paper, is a kind of office automation, industrial information paper, widely used in all walks of life in the office affairs of forms, invoices, bills, labels, credit CARDS, as well as the display of instruments and meter recording media. Carbonless carbon copy paper is a frequent physical evidence at crime scenes, especially in cases involving economic disputes, carbonless carbon paper may be the direct and important physical evidence in case detection, so the analysis and examination of carbonless carbon paper material evidence plays an important role in serial cases and case detection. The purpose of this paper is to study the application ability of ultraviolet spectroscopy in the handwriting test of carbonless copied documents. In this experiment, infrared spectrum analysis, ultraviolet spectrum analysis, and first-order derivative spectrum analysis were used in the scope of the experiment to test the handwriting of carbon-free carbon copy documents. Firstly, mathematical statistics were used to analyze the composition and content of invisible ink in the carbon-free carbon copy paper of express delivery companies. Then the data statistical method was used to classify and analyze the adhesive content and composition of each paper company. And the advantages and disadvantages of using single variable method to compare UV spectral analysis and first derivative spectral analysis. Experimental data show that Shentong express and EMS are likely to use the same brand of the same type of processing in the factory without carbon carbon paper; according to the composition of the adhesive, we can analyze the different characters of carbon-free copies. That belongs to enjoy the company of no carbon carbon content I class, while the red and no carbon carbon composition of Jin Yi company belongs to II class category, peak company belongs to III class. Experimental data show that according to the combination of adhesive components, different carbon-free carbon copies can be analyzed. That belongs to enjoy the company of no carbon carbon content I class, while the red and no carbon carbon composition of Jin Yi company belongs to II class category, peak company belongs to III class. The experimental data show that the method of ultraviolet spectrum analysis established in this paper can be used to test the carbon-free carbon carbon copy added or altered in suspicious documents, and improve the accuracy of 34.45% for the color trace analysis of carbon-free carbon paper.