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Related Concept Videos

Indicators02:39

Indicators

Certain organic substances change color in dilute solution when the hydronium ion concentration reaches a particular value. For example, phenolphthalein is a colorless substance in any aqueous solution with a hydronium ion concentration greater than 5.0 × 10−9 M (pH < 8.3). In more basic solutions where the hydronium ion concentration is less than 5.0 × 10−9 M (pH > 8.3), it is red or pink. Substances such as phenolphthalein, which can be used to determine the pH of a solution, are called...
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Qualitative Analysis

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Differential Staining Technique01:26

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Related Experiment Video

Updated: Jul 15, 2026

Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
09:46

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Published on: August 19, 2013

Identification and differentiation between colored pencils.

O Hilton

    Forensic Science
    |December 1, 1975
    PubMed
    Summary

    Visual examination is key for distinguishing colored pencils. Additional tests like infrared luminescence and ultraviolet radiation help differentiate similar shades and establish pencil origins.

    Area of Science:

    • Forensic Science
    • Material Analysis
    • Document Examination

    Background:

    • Colored pencils are common writing instruments with diverse shades.
    • Distinguishing between different brands and grades of colored pencils can be challenging.
    • Existing methods for pencil analysis may not fully differentiate subtle variations.

    Purpose of the Study:

    • To evaluate various analytical techniques for differentiating colored pencil strokes.
    • To determine the effectiveness of different methods in distinguishing between pencil makes and grades.
    • To establish a comprehensive approach for colored pencil analysis.

    Main Methods:

    • Visual examination of pencil strokes.
    • Infrared luminescence and radiation analysis.

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  • Ultraviolet radiation examination.
  • Chemical spot testing.
  • Study with dichroic filters.

    • Main Results:

    • Visual examination is the primary method for distinguishing pencils.
    • Infrared luminescence and ultraviolet radiation are effective for red, blue, and green pencils.
    • Specific tests show varying degrees of utility depending on pencil color.
    • Combinations of tests enhance the ability to differentiate similar pencil strokes.
    • While not all makes are distinctive, significant variety exists within color groups.

    Conclusions:

    • Multiple analytical techniques, beyond visual inspection, can differentiate colored pencil strokes.
    • The effectiveness of methods like infrared and ultraviolet examination varies by color.
    • A combination of tests provides robust differentiation of colored pencil makes and grades.
    • This study aids in forensic analysis and material identification of colored pencil markings.