Chapter 1,198 One is on the ground and the other is in the sky
This new technology of principal gold decoration is to dissolve gold powder in glue, and then use a brush to draw the porcelain decoration, commonly known as "gold tracing". This is principal gold decoration.
In the fifty-first year of Kangxi's reign (1712), the Jesuit missionary Antrecolay (Yin Hongxu) mentioned the preparation method of Jingzhen gold color in his letter to Father Ori.
If you want to get a gold color, grind the gold into pieces, pour it into a porcelain bowl, and mix it with water until a layer of gold appears at the bottom of the water.
Keep it dry at ordinary times. When using it, take part of it, dissolve it in an appropriate amount of rubber water, and then add lead powder.
The ratio of gold to lead powder is thirty to three.
The method of applying gold color to the porcelain body is the same as the method of applying color.
This kind of gold color is drawn with gold powder, baked at low temperature, and then rubbed with agate rods or quartz sand, which can produce a golden luster and achieve a gold plating effect.
Compared with the previous gold foil gilding, the gold tracing pattern is more detailed and vivid, and the gold powder is more closely integrated with the utensils and is not easy to fall off.
Of course, it is not very simple to operate.
The operation process is divided into five parts. The first step is to beat the gold powder.
This step is not simple. First, the gold foil must be placed in the porcelain gold beating plate.
Then add an appropriate amount of water, heat it to about 40°C, grind it continuously in the plate with your hands to turn it into gold powder, and then use a 1200-mesh sieve to fineen it.
The second step is to add 0.5% western red with a principal amount of 1 point, and mix it in a palette.
Then add 5-6 drops of gum solution and adjust until the gold powder does not foam.
Put the color-adjusted plate on a bowl of hot water and scald it dry.
Then use a gold tracing pen, dip it in water to add gold, and depict the patterns.
The last step is to use an agate pen on the gold after firing to scrape out the golden shine, or rub it with fine sand.
It is very difficult to process gold-colored porcelain with principal money.
First of all, the gold should not be too thick. If it is too thick, the color will be gray and it will easily cause "undressing" (that is, the gold will fall off).
Secondly, when using gold, it should be applied in one stroke without any additional filling, otherwise it will also affect the color and cause "undressing".
In addition, the use of water should be appropriate. Too little water can also cause "undressing".
In winter, the glue is easy to freeze, so it is better to mix the gold powder with garlic juice.
The final firing temperature should not be too high, otherwise the gold will turn rose or purple and lose its luster.
Technology progressed slowly step by step, so in the late Qing Dynasty and the Republic of China, foreign gold decoration became popular.
In 1830, Ju En, a Japanese man, created "Golden Water".
That is, gold is dissolved in aqua regia, which is a mixture of concentrated nitric acid and concentrated hydrochloric acid in a volume ratio of 1:3.
After the gold is dissolved in aqua regia, it is then painted.
This gold color production method was introduced into China during the Opium War in 1840 and was applied to the production of Jingzhen porcelain. It is called foreign gold technology, also known as: bright gold or gold water.
The advantages are very outstanding, first of all, the golden hair color is good, shiny and smooth.
Secondly, the gold color coating is thin, which greatly reduces the amount of gold used.
The most important thing is that the process is simple and does not need to be polished after leaving the kiln like the original.
Finally, the most important advantage is that the gold color has good adhesion, which improves product quality.
Therefore, for crafts such as gold color, the more modern times, the higher the level of craftsmanship, the more beautiful the gold color porcelain produced.
However, this modern craft is very different from ancient craft.
It’s even obvious at a glance. If you are making antique porcelain, you must be careful not to make it too good. Otherwise, a discerning person will know it is a modern handicraft at a glance.
Of course, the advantages of modern craftsmanship are still great, so if you want truly good gold-color craft porcelain, you still have to look at some modern works.
For example, Mr. Kai Shenchang during the Republic of China made some custom-made porcelain.
Among the representative works that use gold color, there is a pair of gold-ground pastel consecrated four-season landscape amphora.
Although this kind of handicraft has a short history, it is custom-made porcelain from Zhong (Kaishenchang).
Therefore, the value of gold color sometimes really does not depend on the time it exists.
Of course, we don’t just look at the quality.
Sometimes this kind of craftsmanship can double the value of a piece of porcelain, and sometimes, when gold appears on some porcelain, it will be deeply engraved with a name: fake!
Let's not talk about fakes, let's talk about genuine ones. Just because they were produced in different periods of history, the "golden colors" that look exactly the same will have actual values one on the ground and one in the sky!
At this point, it is very important to understand the evolution of gold color in porcelain.
To put it simply, it is just gold foil in the Song Dynasty, principal gold in the Ming and Qing Dynasties, foreign gold in the late Qing Dynasty, and modern chemical gold.
So what is the difference between "principal gold", "foreign gold" and "chemical gold"?
In fact, it is very easy. Domestic ceramics have always been like a tall pine tree, dividing the historical trajectory with its annual rings and recording technological innovations with its branches.
One of them, "Golden Color", is particularly eye-catching.
As a porcelain-making process that uses gold to make colored materials for decoration, gold-colored porcelain has the inherent golden halo of gold, which is particularly eye-catching among various patterns.
The industry generally believes that gold-colored porcelain began in the Song Dynasty, among which Ding kiln gold-colored porcelain is the most famous.
During the Hongwu period of the Ming Dynasty, Jingzhen also produced gold-colored porcelain, which was most popular in the Qing Dynasty.
The evolution of "gold color" in gold-colored porcelain, the most critical "gold color material", has different production techniques in different periods.
As mentioned before, gold foil from the Song Dynasty, principal gold from the Ming and Qing Dynasties, foreign gold from the late Qing Dynasty, and modern chemical gold.
Chen Wenzhe had learned the gold foil gilding technique before. The gold-colored porcelain laminated with gold foil has a high integrity, uniform and bright color, and good adhesion.
However, because it is glue-pasted, the edges are a bit stiff and not as smooth and natural as the later gold tracing with principal or foreign gold.
Also, although gold foil has good integrity, its cost is also high.
Therefore, during the Kangxi period of the Ming Dynasty, a new "gold color craft" appeared - principal.
Compared with gold foil gilding, the gold painting process is more complicated.
Therefore, the emergence of foreign gold provides another option for the production of gold-colored porcelain.
Yangjin eliminates the tedious grinding and polishing process. You only need to use a gold tracing pen and dip it in gold water to draw the pattern according to the decorative parts. It is easy to operate;
The layer of gold water is thinner, which reduces the amount of gold used and saves costs while ensuring bright and smooth color quality;
The adhesion of gold is also further strengthened, improving quality.
In the late Qing Dynasty, many daily porcelains used foreign gold as the decorative material.
However, compared with principal gold, foreign gold lacks durability and is easy to peel off after long-term use. Therefore, high-end porcelain is still mostly made of principal gold.
All of this is actually to simplify the process, and simplifying the process is ultimately to save costs.
When it comes to saving costs, is there any way to save money than using chemical gold?
Modern gold-colored porcelain is also more technological, so the emergence of a new type of "gold-colored", that is, chemical gold, has become inevitable.