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영어

Just like other archaeological studies, the success of petroglyph researches heavily depends on precise records. Imprecise records of rock surfaces would make any interpretations of petroglyphs impossible.
The existing method of petroglyph recording has been lacking objectivity and preciseness and more importantly, doing considerable damage to valuable petroglyphs with some of them irrevocably damaged already.
Therefore, the recording of petroglyphs is closely linked to their conservation. One of the ways to solve the problem is non-touching method; that is not to put hands or any other objects directly on rock surfaces. One example is digital surveying which has seen rapid development recently. Another way is photographic surveying. There are many affordable and easy-to-use softwares available so that researchers can measure and record petroglyphs themselves without much cost and any damage to rock surfaces.
The following is the photographic surveying method I use.
1) Install grids on rock surface. 50 centimeter by 50 centimeter is most common for each grid, but depending of the size of the rock, it can be made bigger or smaller.
2) Photos are taken at night by grid. The camera is placed at the right angle to the rock surface at a distance so that each grid comes within the viewfinder.
3) Four photos are taken for each grid. Each shooting is accompanied by artificial lighting from one of four directions; top, bottom, right, and left.
4) Since the four photos have different positions of shadows, the carved 1 ines of petroglyphs can be represented precisely.
5) Overlap the four photos and adjust the contrast using a Photoshop software with a proper filter and you can get a precise image of the rock surface.
6) Connect the photos of each grid using the photo connection function of the Photoshop.
7) In the case a precise image has not been obtained, enlarge the photo on the monitor to do some additional adjusting work manually.