The RT100 and RT200 combine advanced microspectrometer technology with the computing power of a PC.  The spectrometer units link to a standard PC computer with Lovibond RT Colour Measurement System software installed for instrument operation and for presentation, analysis and logging of reflectance data.  Results can be expressed in a choice of colour values and colour difference measurements: X Y Z tristimulus values, CIE L*a*b*, CIE x y Y, CIE L’u’v’, CIE L*C*h, Whiteness Index, Yellowness Index, △E, △L*, △a*, △b*, △C*, Dh colour differences, reflectance, metameric index.

The software, which works under MS Windows 95/98/NT, displays a choice of colour spaces or reflectance curves, allows input and selection of reference values, will average multiple measurement and includes a verbal indication of colour differences.  It includes the facility for data export to ASCII files and direct data export into MS Excel.

不適合使用本儀器之狀況如下:
Do’s and Don’ts in Colour Measurement with the RT100

1. Try to have clean sample surfaces.  Fingerprints, scratches, dust, dirt, residual cleaning agents may affect the results.

2. Averaging of several measurements across the sample is advisable.

3. With non-ideal samples, the reproducibility of subsequent measurements has to be checked.  If the differences are too high, try averaging (see 2.)

4. Fold translucent samples to have sufficient optical thickness.  Alternatively measure with defined background (white and/or black).

5. A large number of samples have temperature dependent colours (thermochromic effect).  Only a few degrees’ temperature change can cause significant colour differences.

6. The calibration of spectrophotometers is carried out using white (and in some cases black) standards.  Their quality and condition affect the absolute accuracy of the measurements!  Pay attention to the time between calibrations, especially with changing ambient temperatures.

7. Fluorescence can be difficult, because besides reflecting the light from the illumination, the sample itself emits light.  The measuring results are affected not only by the sample properties, but also by the illumination used in the spectrophotometer.  So only relative measurements are advisable.

8. Metamerism.  Two samples which look equal under one illuminant may look different under a different illuminant.  This is caused by the different spectral reflectance properties of the two samples.