Why did Lao Fengxiang only write enough silver in his silver ornaments?

Lao Fengxiang's silver ornaments must be marked on the jewelry, because the symbol of foot silver is a national compulsory symbol.

Lao Fengxiang is just a company, and its trademark is a merchant, not a supplier of jewelry raw materials. The foot silver logo is mandatory by the state, so it will definitely be marked on jewelry. State regulations on these precious metal products.

Generally, the manufacturer's code, material name and content stamp are required. As a silverware dealer, Lao Fengxiang doesn't produce silverware, so he can't label jewelry. If he marks it, it is cheating consumers.

Brief introduction of foot silver

Foot silver is a Chinese word, which means silver with perfect color. According to international standards, foot silver refers to silver with a silver content of not less than 990, which is generally processed into bracelets, pendants, longevity locks and other silver ornaments. Foot silver jewelry usually has several signs, one is S99, the other is S990, and S is the initials of the English word Silver, which stands for silver, with the contents of 999, 990 and 920.

Silver is of great significance in the manufacture of photographic photosensitive materials, because the sensitizers coated on photographic paper and film are all silver compounds, such as silver chloride or silver bromide. These silver compounds's are very sensitive to light, and they decompose as soon as they encounter light, with much decomposition in strong light and less decomposition in weak light.

But at this time, the image is only faintly visible and must be revealed to be clear and stable. After development, it is fixed and unexposed excess silver chloride or silver bromide is removed from the negative. Contrary to the real scene, the image on a negative is called a negative-where the light is strong, silver chloride or silver bromide is much decomposed.

The black on dark black film is very fine metallic silver, but the place with weak light appears whiter. When printing a photo, the black and white of the photo is opposite to the black and white of the negative, so it is consistent with the tone of the real scene. Modern photography technology has been able to take very clear photos in a few tenths of a second to a few hundredths of a second under the weak match light.

Today, the world's silver used for film and photography has reached 150 tons every year.