채색문화유산은 종이, 견, 나무, 흙, 회 등 다양한 재료를 바탕재로 사용하여 그 위에 먹 등으로 밑선을 그리고 여러 가지 색료를 이용하여 선이나 색채를 표현한 것이다. 먹선은 본래의 도상을 확인할 수 있기 때문에 모사와 보존처리 시 그 중요성이 강조되고 있다. 이에 적외선 촬영을 이용한 먹선 분석이 광범위하게 수행되고 있다.
본 연구에서는 채색문화유산의 바탕층 재료에 따른 적외선 촬영법을 사용한 밑선의 검출 영향을 연구하였다. 확인에는 적외선 촬영법에 사용되는 적외선 카메라와 900~1700nm영역을 검출할 수 있는 초분광 카메라 2종의 검출기기를 이용하였다. 밑선 검출을 위해 지류(닥지, 쪽/닥지), 직물(견, 견/연백), 목재(뇌록/목재), 토벽(뇌록/토벽), 회벽 7종의 바탕층 위에 먹으로 ‘檢’를 표기하고 진사, 석황, 석록, 석청, 연백, 연단 6종의 상부 채색층을 구성하였다. 시료 제작 후 적외선 촬영법을 이용하여 밑선을 검출한 결과는 다음과 같았다. 지류와 직물 바탕재의 경우 먹선 검출에 미치는 영향의 차이가 미미하였으며, 지류에 쪽을 염색한 경우와 견에 연백으로 배채한 경우에도 큰 차이점이 확인되지 않았다. 단, 목재, 토벽, 회벽의 경우 먹선 검출에 큰 영향을 미치는 것으로 확인되었다. 특히 뇌록을 가칠로 적용한 목재와 토벽의 경우 6종의 상부 채색 안료에 대하여 모두 먹선이 검출되지 않았으며, 회벽의 경우에는 석록을 제외한 모든 상부 채색 안료에서 먹선 검출에 보다 긍정적인 영향을 미치는 것으로 확인되었다.
본 연구를 통하여 바탕층의 재료에 따라 먹선의 검출 효율에 미치는 영향이 확인됨에 따라 채색문화유산 조사 계획수립 및 결과 해석에 활용될 것으로 기대된다.
Painted Cultural heritage uses various materials such as paper, silk, wood, soil, and lime as a base layer to draw on using ink sticks and express lines or colors using various colorants. The importance of underdrawings is emphasized when it comes to replication and preservation, as they can reveal the original drawing. Investigations using infrared have been extensively conducted to detect underdrawings. However, there has been a paucity of research on the influence of underdrawing detection according to the base layer.
In this study, the effect of the base layer materials on underdrawing detection in painted cultural heritage was confirmed using an infrared camera and hyperspectral camera (900 to 1700 nm). The study samples marked ‘檢’ with ink below the color layer (cinnabar, orpiment, malachite, azurite, white lead, and red lead) by the base layer materials: Paper (Dakji, indigo/Dakji), silk (silk, silk/white lead), wood (celadonite/wood), soil (celadonite/soil), and lime. The difference in the effect on underdrawing detection was minimal for paper and silk, and no significant differences were found between Dakji and indigo/Dakji, or between silk and silk/white lead. However, we found that celadonite/wood, celadonite/soil, and lime have a significant impact on underdrawing detection. In particular, for wood and soil painted with celadonite, underdrawings were not detected for all six color layers. In the case of lime, it was found that all color layers except malachite had a more positive effect on underdrawing detection.
The findings of this study will aid in selecting the appropriate method for underdrawing analysis in the restoration of painted cultural heritage.
This paper aims to present a digital recording method of relics utilizing open-source software and photogrammetry technology, which is believed to be the most efficient method among 3D scanning methods. The digital recording process of relics consists of three stages: acquiring a 3D model, creating a joining map with the edited 3D model, and creating an digital drawing. In order to enhance the accessibility, this method only utilizes open-source software throughout the entire process.
The results of this study confirms that in terms of quantitative evaluation, the deviation of numerical measurement between the actual artifact and the 3D model was minimal. In addition, the results of quantitative quality analysis from the open-source software and the commercial software showed high similarity. However, the data processing time was overwhelmingly fast for commercial software, which is believed to be a result of high computational speed from the improved algorithm.
In qualitative evaluation, some differences in mesh and texture quality occurred. In the 3D model generated by open-source software, following problems occurred: noise on the mesh surface, harsh surface of the mesh, and difficulty in confirming the production marks of relics and the expression of patterns. However, some of the open source software did generate the quality comparable to that of commercial software in quantitative and qualitative evaluations.
Open-source software for editing 3D models was able to not only post-process, match, and merge the 3D model, but also scale adjustment, join surface production, and render image necessary for the actual measurement of relics. The final completed drawing was tracked by the CAD program, which is also an open-source software.
In archaeological research, photogrammetry is very applicable to various processes, including excavation, writing reports, and research on numerical data from 3D models. With the breakthrough development of computer vision, the types of open-source software have been diversified and the performance has significantly improved. With the high accessibility to such digital technology, the acquisition of 3D model data in archaeology will be used as basic data for preservation and active research of cultural heritage.