1. A comparative study of ballpoint ink ageing parameters using GC/MS
Agnès Koenig, Sophie Magnolon, Céline Weyermann 
Forensic Science International 
Volume 252, Pages (July 2015)
DOI: /j.forsciint
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2. Fig. 1 Sample collection procedure [14,21].
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3. Fig. 2
Ageing curves obtained for 1–395 days-old samples from ink 1688: (A) quantities of PE recovered in natural and heated samples; (B) calculated R%; (C) RPA(PE/BA); (D) (R%* calculated from RPA(PE/BA). The inflexion intervals at which the 1st falling rate did not significantly contribute to the regression anymore are indicated with grey dotted lines.
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4. Fig. 3
Ageing curves of the quantity of PE recovered in the heated samples of ink 1688, 1774 and 1892.
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5. Fig. 4
Ageing curve of the different solvents present in ink 1688 (A), in ink 1774 (B) and in ink 1892 (C). IS, Internal standard; PEE, Phenoxyethoxyethanol; BA, Benzyl alcohol; HG, Hexylene glycol; DPG, dipropylene glycol; DMCH, dimethylcyclohexadienone.
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6. Fig. 5
Ageing curve of ink 1688, 1774, 1892 stored in the laboratory and built with: (A) the natural quantities of PE, (B) ratios of ink compounds, and (C) R% calculated with RPA.
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7. Fig. 6
Ageing curve of ink 1688, 1774, 1892 stored in the climatic chamber and built with (A) quantity of PE, (B) RPA(PE/BA), and (C) R%*.
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8. Fig. 7
Influence of different initial writing pressures on the ageing curve of ink 1688: 100g, 250g, 350g as well as lines written with uncontrolled pressure from two different •writers. Three ageing parameters were represented (A) Quantity of PE, (B) RPA(PE/BA), (C) R%*.
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9. Fig. 8
Normalisation of the ageing curves obtained for different writing pressures using the ink line surfaces of ink 1688 (mm2) for: (A) the natural quantities of PE, (B) R%*.
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