Color extends beyond a qualitative measure and can also be compared between laboratories when it is properly calibrated to account for the effects of illumination conditions and camera devices . Methods such as 3-dimensional thin plate spline or root-polynomial regression are applied to convert the colors seen by the camera to the colors they would look like under a standardized reference illuminant using a reference color chart as a basis for the transformation , . Calibrated color has been previously introduced as a quantitative metric to evaluate dye solar cell degradation , and is used especially in color analysis applications that involve multiple devices or sites. Furthermore, calibrated color is useful when small-area colorimeters are not sufficient due to the spatial variability of the samples such as in the food industry , , .