Korean paintings are usually painted on paper or silk fabric. Various traditional mounting techniques, such as hand scrolls, hanging scrolls, screens, and painted plates, are used in order that the viewer can appreciate the work better. Most paintings were remounted a number of times as they were handed down to us today. There were many cases that the condition of the paintings deteriorated due to an unsuitable remounting process. This means that there are very few works that have been able to maintain their original features. Through the restoration of a work, there is a variety of information we can obtain including the traditional style of the mount, the material used, as well as the color and technique. However, in works that have already been damaged from remounting, then it is very difficult to obtain precise information. A silk support painting The Portrait of Song Shi-yol that had never once been remounted and thus was able to maintain its original style constitutes the main focus of this paper. Through its restoration process, we were able to obtain some information that was then recorded. The most important step, in the process of restoration, the replacement of first lining, is what this paper would like to touch on. The fabric support paintings generally consisted of silk and in most cases it was plain weave. The density of the fabric and the thickness of its strands were irregular. From its half-transparency, its backside was colored flatly in advance and the front side was drawn and colored. This way of painting was used often for Buddhist paintings and for portraits. In the case of this painting, parts of the backside painting technique that were not able to be discerned with the naked eye because the entire front suffered from either coloring that had changed or become faded, were examined using X-ray radiography. Aside from the unpainted parts and the drawn parts painted with Chinese ink, it was confirmed that the remaining portions of the figure were colored by the backside painting technique. At the same time, XRD analysis revealed that the pigment of color on the backside and that of the white color used on the front side were the same kind of lead white. In removing the previous linings, it was found that the unpainted parts had become so moth-eaten that they had to be removed entirely. In order to protect the color on the backside painted parts, the previous linings were not completely removed, but rather left in a thin layer. In order to minimize the difference of thickness between the unpainted part and the backside painted parts, first lining paper of differen thickness was used so that the entire thickness of the surface could be adjusted. In addition, it was examined by the SEM that bamboo paper was used on the previous lining. The restorers decided that bamboo paper woul be replaced Korean mulberry paper. The reason is, in the case of silk support paintings, with the passage of time, the silk itself loses its strength and the first lining has the job of supporting the silk part. In comparison to Korean mulberry paper, however, bamboo paper's fibers are weak and so, it is considered a very unsuitable fabric for lining. First linings can be considered the most important step in the process of restoring a painting. When lining paper is replaced, the glue used or mulberry paper, if properly manufactured using traditional techniques, plays the role of neutralizing oxidized paper. Use of this material for first linings ensure that the work can be recovered in stable condition. Even paintings restored in this manner will still see some oxidization after the passage of time, which means that it will be necessary to repeat the restoration process. One should always consider the next restoration, and choose and use materials that are easily restorable.