Construction of Spectral Discoloration Model for Red Lead Pigment by Aging Test and Simulating Degradation Experiment

Table 7

values of different fitting functions at 700 nm.

Functions
Exponential	0.92245
Linear	0.63268
Logarithmic	0.99515
Polynomial	0.84378
Power	0.82483

Note: “polynomial ” represents the two-order polynomial.