Thin Layer chromatography is a widely employed analytical tool of mainly a qualitative nature. To obtain quantitative remits, the separated components can be scraped-off together with the sorbens layer, eluted and determined e. g. spectrophotometrically. Often, colour development by treatment with suitable chemical reagents is required as an intermediate stage. The application of photodensitometry, i. e. measuring the TLC plate optically, whilst highly advantageous in overcoming the cumbersome elution technique particularly in terms of time saved, has some serious limitations, often leading to incompatible quantitative results. Apart from the fact that the mechanism of light absorption in light scattering media is not yet fully understood, most densitometers are of the linear scanning type (slit scanners) which are unsuitable for TLC scanning as will be explained later. However, an advantage of densitometry, is that an objective picture of the chromatogram is obtained and that the properties of a chromatographic separation can be recorded in terms of plate number, HETP and resolution of a pair of components