The Fundamental Researches for Discoloration and Recovery of Lead Glass Pigments for Japanese Style Paintings

铅玻璃颜料是日本风格绘画中最流行的绘画材料之一。我们检查了铅玻璃颜料的变色情况。首先，我们确认了铅玻璃颜料的图片上有暗银灰色的部分。在这一部分中，对PBS进行了检测。这张图片有HGS的底色层，可能是铅玻璃与来自HGS的S^&lt；2-gt；2-gt；接下来，我们研究了各种气体对铅玻璃颜料(样色：粉色、黄色、绿色、淡蓝色和灰色)的影响*SO_2 10ppm，高湿度，20ﾟC，20小时后黄色变成棕色，灰色变成象牙色，其他颜色变亮。*H_2S 10ppm，高湿度，20ﾟC，20小时，所有颜色均为深褐色。*甲醛25ppm，高湿度，20ﾟC，20小时，颜色变化不确定。在1)或2)情况下，白垩层对酸性气体起到了缓冲作用。经过1)实验，我们尝试恢复，使用O_3。淡蓝色和灰色颜料略有恢复其蓝色。但测试板表面仍有一些模糊现象。

Lead glass pigments ("Shin-iwaenogu" are one of the most popular painting materials for Japanese style paintings. We examined the discoloration of lead glass pigments.First, we confirmed that there were dark silver gray parts on the picture of lead glass pigments. In this part, PbS has been detected. The picture had foundation layr of HgS.Possibly, lead glass interact with S^<2-> from HgS.Next, we examined what various gases influence lead glass pigments (sample colors : pink, yellow, green, pale blue, and gray)* SO_2 10ppm, high humidity, 20ﾟC,20 hoursYellow color turned to brown, gray color changed to ivory, and other colors were brighten. Various product may have formed on pigments.* H_2S 10ppm, high humidity, 20ﾟC,20 hoursAll colors were dark-browned. Some sulfides may have formed on pigments.* Formaldehyde 25ppm, high humidity, 20ﾟC,20 hoursChanges of color were not confirmed.At 1) or 2) cases, foundation layr of chalk have playd the part of buffer to acid gases.After 1) experiment, we try to recover, using O_3. Pale blue and gray pigments recovered their blueness slightly. But some blurs remained on surface of test panel.