Documentation by Drawing, Tracing and Photocopying

Even today, thin-layer chromatograms are often drawn or traced on tracing paper, and the zones are then colored with colored pencils (Fig. 99). These methods are time consuming, and the fine color nuances can seldom be accurately represented. Nevertheless, these methods of documentation are perfectly acceptable for legal purposes [125]. 

To illustrate this theme, the cartoon below shows a young man somewhat laboriously tracing thin-layer chromatograms, while the girl is using modern video equipment for the documentation of a TLC plate. 

Photocopiers are also used for documenting TLC results. However, as color copiers are rarely available, the colored chromatograms are reproduced in black and white only. It is also a disadvantage that documentation directly under UV light is not possible. 

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