In the gradient method, the liquid crystal is subjected to a variable color-temperature distribution such as a linear temperature gradient. Thus, this technique establishes a hue-temperature calibration over the full range of colors displayed by wide-bandwidth liquid crystal, typically those with a bandwidth of several degrees Celsius or more. The benefit of this approach is that, it provides a continuous representation of the entire color temperature response of liquid crystals using a single color image. It provides a higher color temperature resolution than the successive isotherm method in a fraction of the time and with much less data processing.

Several factors impact the accuracy of liquid crystal measurements. These include

1. irregularities in the liquid crystal layer
2. incident light reflected from the liquid crystal sheet
3. variation in the lighting/viewing angle across the surface
4. variation in temperature of the calibration surface
5. ambient lighting condition, camera conditions (such as circuit gain, filter adjustment, aperture and optical adjustments)
6. characteristics of the transparent surface through which the LCs are viewed
7. hue evaluation technique
8. hysteresis effects

Past investigators have systematically studied and evaluated the effect of these factors. Definitive recommendations are available that reduce the adverse impact of these problems. Recent investigations (Sabatino et al. 2000, Smith et al., 2001) summarize the overall procedure to be followed for LCT measurement of temperature.