How did the ancients extract cyan?

This article is selected from A Brief History of Cyan.

Author: Bao Yan

Cyan is a widely used color on ancient fabrics. In the Seven Exhibitions of Heavenly Creations, it is clearly recorded how the ancients extracted cyan dyes from plants.

If you want to create different shades of cyan, you only need to have some skills in dyeing process. "All five blues can be lakes." From how to plant to how to extract dyes, Tiangong Wu Kai gave a detailed description. For example, Isatis indigotica (Isatis indigotica) is easy to cultivate, and it can live after taking root, while cymes, Malan and Wulan all need sowing.

In the Ming dynasty, people found a better plant to extract indigo than Isatis indigotica-Polygonum cuspidatum, lobular, commonly known as amaranth. Indigo extracted from Polygonum cuspidatum is thicker and more shiny than the blue dye extracted from Radix Isatidis, and it is not easy to fade and has a better variety. Later, it was this kind of Isatis indigotica that was introduced to Europe, which eventually destroyed the cultivation and printing and dyeing industry of Isatis indigotica in Europe for centuries.

Tying Wu Kai also explains how to make indigo. For example, if the leaves and stems of plants are more, they will go directly into the cellar, and if the leaves and stems are less, they will be soaked in barrels or tanks. "After seven days of soaking in water, the juice will come out." Until these plants ooze blue juice, each stone juice is put into five liters of lime and stirred for dozens of times, and indigo condenses. Then, when the water settles, indigo will sink to the bottom.

Tiangong Kaiwu also records in detail how different colors are made. For example, sky blue can be obtained by putting the fabric in an indigo vat and dyeing it light blue, and then dyeing it with hematoxylin (red and yellow). The so-called registration dyeing is to put the same fabric into a vat of different colors and finally get the third or fourth color.

To dye grape blue, first put the fabric into an indigo vat to dye it dark blue, and then put it into sappan water for over-dyeing. To dye egg blue, first dye it with phellodendron amurense, and then put it in an indigo vat. To dye turquoise blue and sky blue, you can only dye it in indigo vats, but the shades are different.

Dye dark black, first dye dark blue with indigo water, then boil water with reed wood and bayberry peel, and then register for dyeing.

Moonlight and grass can be slightly dyed with indigo water, or dyed with amaranth boiled water when it is half cooked.

Interestingly, Tiangong Kaiwu also specifically mentioned how to dye the blue headscarf used in the head. Although it is dark blue, it is not dyed with indigo. Instead, cook chestnut shells or lotus seed shells for one day, filter them out, put them in a pot, add iron ore and soap alum, and then cook the fabric overnight to become dark blue and black.

The need of painting art makes cyan pigment change with each passing day. One kind of pigment is extremely precious, which is made by grinding and precipitating precious stones, that is, ultramarine blue ground by lapis lazuli. Ultramarine blue is expensive, and its refining process is complicated. It is often used in murals and royal decorations in religious places. In the western suburbs of Beijing, there is the Imperial Temple of Amin Dynasty, fahai temple. The murals in the temple are so beautiful. Among them, the aura and ornaments of Shuiyue Guanyin Bodhisattva Samantabhadra and Manjusri Bodhisattva use a lot of mineral pigments, including lapis lazuli.

Zhang Shoufan talks about lapis lazuli in Mineralogy, which is "used to make the most expensive cosmetics, utensils and blue pigments". Precious paintings in Chinese and western paintings are all painted with this pigment. For example, the blue of the Buddha statue in Mogao Grottoes is lapis lazuli.

In Europe in the17th century, painters learned about this gem pigment from the Middle East or Asia, but it was rarely used because it was very expensive. The Dutch painter Vermeer painted many clever girls. He often uses blue in these paintings, but only uses ultramarine as the surface color-that is, when painting, he will use azurite or other colors as the background color, and finally paint a thin layer of ultramarine on it.

Because ultramarine is very expensive, painters can't always afford it, so they often use another blue-azurite. Azurite, also known as azurite, is divided into Touqing, Qing Er, Sanqing and Siqing according to the different refining times. In Chinese painting, Sanqing is the most common one.

The coverage of azurite is particularly good. Even when painting Chinese painting, it can be operated like oil painting, and it can be covered layer by layer after drying. Therefore, painters think that azurite is easy to use when painting landscapes, which is more conducive to painting the yin and yang, depth and height of mountains. 165438+At the end of the 20th century, Wang Ximeng, a great painter in the Song Dynasty, painted a picture of a thousand miles of mountains and rivers at the age of eighteen, showing the magnificent mountains and rivers in the Song Dynasty. His paintings are magnificent and bright in color, and the bright blue in the paintings is azurite. The color of this mineral has not faded after thousands of years and is still bright and dazzling.

In the 20th century, a great painter Picasso appeared in Europe. He especially liked to paint in blue. The blue colors used are turquoise, cobalt blue and Prussian blue. During the period of 190 1- 1904, Picasso created many paintings with blue as the background or with blue as the main body, and even painted the bodies of characters in blue. During this period, Picasso mainly painted the lower class people to express a kind of melancholy and sympathy.

The painter Van Gogh often paints with blue pigments. However, due to the shortage of funds, the blue pigment he often uses is cheap Prussian blue, such as starry night on the Rhone River and open-air cafes at night.