Research On Lighting Quantity Indexes For Painted Cultural Relics Of Ancient Buildings Under The Coupling Influence Of Light And Humidity

To strengthen our spiritual culture and enhance national self-confidence,general secretary Xi Jinping stressed that "let historical relics live." At present,ancient buildings have begun to open their internal cultural relics to the public.However,due to the poor internal light environment of ancient buildings,the traditional dark environment has seriously affected the viewing effect of painted cultural relics,so the demand for indoor lighting of ancient buildings is becoming stronger and stronger.Light radiation will cause irreparable damage to the painted cultural relics of ancient buildings.The establishment of a set of scientific lighting quantity index can effectively protect the painted cultural relics.At present,the lighting quantity indexes for painted cultural relics of ancient buildings are missing,because the damage law of lighting quantity to painted cultural relics of ancient buildings is unknown.The damage law of museum painted cultural relics studied by the research group in the early stage is not applicable,because the museum is in a constant temperature and humidity environment,while the ancient building is in a natural environment,and the change of temperature and humidity will affect the lighting damage law.The aging experiment under the influence of light,temperature and humidity coupling involves many parameters,complex working conditions and huge workload.Considering that the light reaction is more affected by humidity,therefore,this study took humidity as an environmental variable to study the lighting quantity indexes for painted cultural relics of ancient buildings under the influence of light humidity coupling,so as to fundamentally realize the effective protection of cultural relics.First,the aging experiment of coupling humidity and light was carried out.D55 light sources were used as the experimental light sources,and the honeycomb constant temperature and humidity experimental box was used as the experimental device.The periodic illumination experiments of ancient buildings painting pigments with different illuminance(0 lx,50 lx,100 lx,200 lx,300lx)were carried out under four humidity conditions of 20%,40%,60% and 80%.After measuring the color data of pigments,the color damage degree of pigments in ten cycles were measured by color difference method,and the color damage laws of pigments under different illuminance,humidity and irradiation time were obtained.These laws can provide data support for the next model construction.Secondly,according to the change law of pigment color difference obtained from the aging experiment,the multiple nonlinear regression equation was coded and synthesized by Python software,and the calculation model of pigment lighting damage under the coupling of humidity,illumination and irradiation time was established.The model can calculate the color damage degree of pigment under any combination of illuminance,humidity and irradiation time,and mathematically express the damage law.The four-dimensional damage diagram was used to reflect the damage effect law under multi parameter coupling.Thirdly,based on the calculation model of pigment lighting damage,the illuminance limit and annual exposure limit were calculated when the color painted cultural relics of ancient buildings are obviously faded by D55 light source under different humidity.At this time,the color difference is specified as ΔE=1.6.By unifying the damage changes,it provided targeted protection methods for the lighting quantity indexes for painted cultural relics of ancient buildings.In conclusion,by exploring the damage law of painted cultural relics of ancient buildings under the influence of light humidity coupling,the lighting damage calculation model of illuminance,humidity and irradiation time coupling was established,the four-dimensional graphic expression of the damage law was realized,and the targeted calculation method of lighting quantity indexes was proposed.This study provided a theoretical basis for establishing the lighting standard of painted cultural relics in Chinese ancient buildings.