Research On Virtual Restoration Of Colors And Textures Of Polychrome Statue

Colors and textures are important features for the historical,artistic and scientific values of polychrome cultural relics,which reflect the historical appearance and technology.Natural aging and environmental factors often alter the colors and textures of cultural relics,making it difficult for people to appreciate the initial appearance.3D modeling and computer virtual reality technology provide the possibility of restoring the original appearance of cultural relics.This paper studied the virtual restoration method of color and texture of polychrome statue by taking the polychrome Dharma statue of Lingyan Temple as an example.Aiming at revealing and showing the appearance of the statue in a specific period in history,and providing a set of practical schemes for the virtual restoration of color and texture of similar polychrome cultural relics.Restoration is based on literature review,artistic style research,scientific analysis and simulation experiments.It is realized by 3D scanning,close-range photogrammetry,high-fidelity information3 D modeling,texture mapping and other computer technologies.Literature review clarified the information on the manufacture age,workmanship,painting,protection and restoration of Dharma statue.The study of artistic style shows that the Dharma statue in Lingyan Temple inherit the modeling characteristics of the Dharma statues in Tang Dynasty,and at the same time highlight the characteristics of “Indian”.Dharma clothing only the outermost cassock symbolically retains the Indian tradition,while the rest are all localized mafors,reflecting the mafors has completed a thorough localization reform in the Song Dynasty.Statue is colorful and rich in color,cold and warm colors forms contrast,and the decorative style is of outstanding nationality and folklore.Scientific analysis shows that the inner structure and paint layers of the statue have the characteristics of multi-strata.The thickness of paint layers and layers number are different at different positions,and the thickness of pigment layer,priming layer,binding layer also have obvious difference.The average particle size of different pigments varies greatly.Pigments are mainly natural minerals,such as cinnabar,hematite,red lead,white lead,chalk,kaolin,magnesite,azurite,pyrophyllite,carbon black,etc.Artificial ultramarine,emerald green,chrome yellow,etc.modern industrial synthetic pigments also widely used in Tongzhi period of Qing Dynasty.In addition,organic paints(Rhodamine B)and titanium dioxide are also used in modern topical painting.The chlorargyrite found in the gilding paint layer is the corrosion product of silver foil.High iron clay minerals and silver foil have been used in place of gold foil.Studies proved that the lavendulan is the transformation product of emerald green,and the transformation process has a significant relationship with the thickness of the pigment layer,the thinner the pigment layer,the easier it is to transform.The gilding binding medium used in statue was tung oil,and animal glue was the main binding medium in pigments,rosin resin was also used as adhesive material in Qing Dynasty.The reddish-brown oily material on statue’s face,neck and gilding area is shellac,a reinforcement material for historical restoration.In terms of painting technology,the last painting of Qing Dynasty used the new technology of painting on sticker.Simulation experiments show that the particle size of mineral pigment has a significant effect on the color and texture after painting,and the different glue concentration has a certain effect on the color of painting,but it can be ignored.On the basis of scientific analysis and related research,the physical reconstruction of the colors and textures of the statue can be easily realized by using the same materials and workmanship as the cultural relic.3D modeling practice shows that 3D scanning and close-range photogrammetry are the best methods to build high precision 3D geometry model and high resolution 3D texture model respectively.Based on the mutual matching and registration of different source models,the high precision size information and high resolution texture information can be easily fused to build the high-fidelity information 3D model.Texture mapping technology can be used to reconstruct colors and textures in statue 3D model.Through texture replace on texture image of high-fidelity information 3D model can ensure the accurate matching between color texture and corresponding position of model.Virtual restoration practice has restored the colors and textures of the Dharma statue in Kangxi and Tongzhi periods of Qing Dynasty.In addition,the virtual restoration of color and texture under current preservation situation was also carried out.The restored statue has bright colors and natural texture.It shows the different faces of kangxi and Tongzhi period in three dimensions,greatly expanding the dimension of the statue exhibition.The restoration work has enhanced the understanding of the original appearance of statues and their aging rules.Brought new perspectives and materials for archaeology,art history,cultural heritage and other related research,and also enriched the digital protection achievements of cultural relics.Based on multi-disciplines,multi-methods and multi-technologies,the research reveals the statue’s history,art,preservation status,paint materials,workmanship,aging rule and other comprehensive information,which provides important reference information for the protection and restoration of cultural relics.