单色釉也称一色釉或一道釉。因釉中含有不同的化学成分，在瓷器的坯体上施釉后经窑火烧，呈现出美丽的色泽，即成单色釉瓷器。如釉中含有一定量的铁，经窑火烧成后呈青色，即为青釉瓷器;含有一定量的铜,经窑火烧成后呈红色，即为红釉瓷器。清代单色釉瓷器烧造于被誉为盛世年代的康熙、雍正、乾隆三朝，这三朝的单色釉瓷器是整个清瓷中最精彩的部分之一，无论是仿宋五大名窑还是各式新创釉色产品，都使人感到精雅无比。单色釉被誉为瓷器家族中的“大家闺秀”。

青釉瓷器，历史悠久，可以说是中国瓷器的鼻祖。早在商周时期就出现了原始青瓷，是历代瓷器烧制的主要品种，早期瓷器都为青釉系，如原始青瓷、青瓷、越窑瓷器、龙泉窑瓷等。明清时期瓷器生产虽以青花和各种釉上彩绘瓷为主流，但青釉瓷器的烧制仍持续发展，到了康雍乾时期，因烧制技术的提高，青釉的呈色达到了前所未有的高度。青釉瓷因青釉呈色的深浅不同，出现了翠青、冬青、粉青、豆青、天青、月白色等不同的釉色。豆青色最深，冬青次之，粉青微深，天青偏蓝，月白色最浅。在两千年的岁月中，青瓷以追求自然天成之美，沉静素雅之风格而受到世人的推崇。

豆青釉是青釉中派生出的一种釉色，是宋代龙泉窑青瓷釉色之一。釉面色泽匀润细纹，色如豆青，因此而得名，多为官窑所烧制的玩赏品。清吴伟业《读史偶述》诗之十六：“王府近来新发出，剔红香盒豆青盆。”许之衡《饮流斋说瓷·说彩色》：“豆青、豆绿，此二色宋哥弟窑为最盛。哥窑多作豆绿，弟窑多作豆青，皆滋润莹泽，至为可爱……明以前之豆青，微近黄色，至清则纯近绿色。”可见，明代豆青色釉烧制水平趋于平稳。豆青色釉的基本色调仍以青中闪黄为主，而青色比以前淡雅。清代豆青色釉淡雅柔和，色浅者淡若湖水，色深者绿中泛黄，釉面凝厚。

这款豆青釉盘，器形小巧规整，内外敷施豆青釉，质地厚润清幽，正合古人“类玉”之美称，观之有如青山远黛之美感， 胎体轻薄隽秀，迎光能透，光素无纹，豆青一色娇嫩怡人，光润如玉，犹如大家闺秀，高贵婉约之气质扑人眉宇。底部青花书楷书款，字体清秀工整，神韵雅致俱存，不失为清代单色釉之隽品。

Monochrome glaze, also known as one color glaze or one layer glaze. Due to the presence of different chemical components in the glaze, the porcelain body is glazed and then fired in a kiln to present a beautiful color, resulting in monochromatic glazed porcelain. If the glaze contains a certain amount of iron, and it turns green after being fired in a kiln, it is called celadon porcelain; Red glazed porcelain refers to porcelain that contains a certain amount of copper and turns red after being fired in a kiln. The single color glazed porcelain of the Qing Dynasty was fired during the Kangxi, Yongzheng, and Qianlong dynasties, which are known as the prosperous era. The single color glazed porcelain of these three dynasties is one of the most exciting parts of the entire Qing porcelain, whether it is imitating the five famous kilns of the Song Dynasty or various newly created glazed products, it makes people feel extremely refined. Monochrome glaze is known as the "lady of a great family" in the porcelain family.

Blue glazed porcelain has a long history and can be said to be the ancestor of Chinese porcelain. As early as the Shang and Zhou dynasties, primitive celadon appeared as the main variety of porcelain fired throughout history. Early porcelain was of the celadon glaze series, such as primitive celadon, celadon, Yue kiln porcelain, Longquan kiln porcelain, etc. During the Ming and Qing dynasties, although the production of porcelain was mainly based on blue and white porcelain and various types of glazed painted porcelain, the firing of blue glazed porcelain continued to develop. By the Kang, Yong, and Qian dynasties, due to the improvement of firing technology, the color of blue glazed porcelain reached an unprecedented height. Blue glazed porcelain has different glaze colors, such as emerald green, holly, pink green, bean green, sky blue, and moon white, due to the different shades of green glaze. Bean green is the darkest color, followed by holly, pink green is slightly darker, sky green leans towards blue, and moon white is the lightest. Over the course of two thousand years, celadon has been highly praised by the world for its pursuit of natural beauty and its serene and elegant style.

Douqing glaze is a type of glaze color derived from celadon glaze, and is one of the celadon glaze colors of Longquan kiln in the Song Dynasty. The glaze has a uniform and smooth color with fine lines, resembling a bean green color, hence its name. It is mostly a decorative item fired in official kilns. In the 16th poem of Wu Weiye's "Occasional Account of Reading History" in the Qing Dynasty, it is written: "Recently, the Wang Mansion has issued a new set of red fragrant boxes and bean green pots." Xu Zhiheng's "Drinking and Flowing Studio Talks about Porcelain – Talking about Colorful Colors" states: "Bean green and bean green are the two colors that were most popular in the Song Dynasty's brother kilns. The brother kilns mostly made bean green, while the younger kilns mostly made bean green, both of which are moist and translucent, and extremely cute… Before the Ming Dynasty, bean green was slightly yellow, but in the Qing Dynasty, it was pure and nearly green." It can be seen that the firing level of bean green glaze in the Ming Dynasty tended to be stable. The basic color tone of the bean green glaze is still mainly green with a shimmering yellow, while the green color is lighter and more elegant than before. In the Qing Dynasty, the bean green glaze was elegant and soft. Those with light colors were as light as lake water, while those with deep colors were green and yellow in color. The glaze surface was thick and condensed.

This bean green glazed plate has a small and orderly shape, with bean green glaze applied on both the inside and outside. The texture is thick, smooth, and clear, which is in line with the ancient reputation of "jade like". It looks like the beauty of a distant and beautiful green mountain. The body is light, thin, and graceful, with light transparency and no lines. The bean green color is delicate and pleasant, smooth like jade, like a lady from a family, and the noble and graceful temperament is striking on the eyebrows. The bottom blue and white calligraphy style is in regular script, with delicate and neat font, and elegant charm, making it a masterpiece of monochromatic glaze in the Qing Dynasty.