Tuesday, June 21, 2011

LOVIBOND TINTOMETER

                The lovibond tintometer on one of the more familiar scientific instruments in th educing trade, In effect it works on exactly the same principle as dyeing to pattern the pattern is matched by means of red yellow an blue glasses which are mixed together until the required shade is obtained . In this instrument the pattern which is being matched is illuminated by an intense light thrown into one half of an eyepiece. the other half of the eyepiece is illuminated by a white light of standard intensity . The colour of this light can be modified by interposing coloured glasses between the light source and the eyepiece.
  VERY BRIGHT COLOURS:
                 It may be mentioned that in certain cases colours occur which are brighter than the colour units employed in the Tintometer . This may frequently happen when one is recording the shades of say dyeings of basic colours on silk . There is of course no glass in the Tintometer scales which compares in brightness with the shade of Rhoda mine silk or of Sulphurous on wool. In such a case it is necessary to introduce neutral tint slices i e grey glasses between the sample under test and the eye of the observer . This is recorded as excess brightness and indicates the amount of light reflected or transmitted by the sample n excess of the light reflected ot transmitted by the Tintometer slides.
                  In the Lovibon Tintometer British drug Houses pattern the number of slides in the standard model No I is restricted to sixty giving twenty of each colour red yellow and blue . It is found that good agreement between observers is obtained when working to this order of colour but Tintomter slides with finer gradations can be prepared for special purposes demanding a higher degree of accuracy.

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