Fig. 2
From: Factorial experimentation on photodegradation of historical paper by polychromatic visible radiation
Scatter plots showing the progression of ΔR over time during the accelerated degradation under eight experimental conditions: a 0% [O2], 70% RH and 20,000 lx; b 0% [O2], 70% RH, 5000 lx; c 21% [O2], 70% RH, 20,000 lx; d 21% [O2], 70% RH, 5000 lx; e 0% [O2], 20% RH, 20,000 lx; f 0% [O2], 20% RH, 5000 lx; g 21% [O2], 20% RH, 20,000 lx; and h 21% [O2], 20% RH, 5000 lx. The trends over the entire time span are approximated using a logarithmic relationship