Pencil has a very long history. It originated in ancient Greece and Rome more than 2,000 years ago. The pencils at that time were very crude, just a lead rod or even a block of lead sandwiched in a metal sleeve. But in terms of its meaning, it is a veritable “pencil”. The pencils we use today are made of graphite and clay and do not contain lead.
The originator of modern pencils was born in the Brodil Valley in the Cumberland Mountains of England in the middle of the 16th century. In 1564, someone in Brodil Valley discovered a black ore called graphite that could be written on. They then cut the ore into thin strips and shipped them to London for sale. The vendors marked them on loan baskets and cargo boxes. Therefore, it is called “marking stone”.
Because pencils made of Brodil Valley graphite are very popular in European countries, the high-purity graphite ore quickly dries up due to excessive mining. So people began to study the use of artificial methods to extract and process graphite.
Shepherds in Barrodale often use graphite to mark sheep. Later, people cut the graphite block into small strips for writing and painting. Soon, King George II of England took the Barrodale graphite mine into the royal family’s possession and designated it as a special product for the royal family. The graphite mine here is like a gift specially given by God for the production of pencils. It is of high purity, smooth and not easy to break. Later, people inserted graphite rods into small drilled wooden sticks to make pencils similar to today’s.
In 1761, the German chemist Van Ba established the world’s first pencil factory. He mixed graphite, sulphur, antimony and rosin into a paste, then extruded it into a strip and dried it, which improved the toughness of graphite and became the prototype of today’s pencil.
However, graphite strips also have its shortcomings: it is easy to get hands dirty, and it is easy to break. In 1761, the German chemist Faber mixed graphite powder with sulfur, rosin, etc. to make a strip, which is much more tenacious than pure graphite strip, and it is not easy to get hands dirty. At the end of the 18th century, only Britain and Germany were able to produce pencils.
Later, France also found graphite ore on its own territory, but the quality of the ore was not high and the reserves were small. Comte, a French scientist, mixed graphite with clay and fired it in a kiln to make a pencil lead that was both usable and durable. The hardness of the pencil lead is different when the ratio of the clay mixed in the graphite is different. We often see letters such as B and HB on the tip of the pencil, which indicate the hardness and color depth of the pencil core. B stands for blackness and H stands for hardness. Therefore, HB is a pencil lead with moderate hardness and color depth, suitable for writing.
Pen cores made of graphite or pigmented clay are used as writing media for writing or painting tools such as learning, office, engineering drawing, fine arts, painting, and various markings. Ancient Greece and Rome used lead metal to make lead rods similar to pencils. This type of pen is often made into a cone, using lead to rub with other objects to leave traces of lead, which are used for marking. In the 14th century, modern pencils appeared in Europe and were used by Dutch painters to paint on paper. The Italians used a mixture of lead and tin to make lead rods for painting and writing. In 1565, in the collection of German C. Gessner, there was a diagram drawn in pencil, and it was recorded that “for drawing and taking notes, people made pen cores from lead and other mixtures, and then attached wooden handles to draw lines. ……”Text. In the same year, Britain began to make the most primitive wooden pencils by hand using graphite as the refill. In 1662, the world’s first pencil factory-Schidelou Pencil Factory was built in Nuremberg, Germany.
In 1761, the German F. Custer founded the Faber Custer Pencil Factory in Nuremberg, using sulfur, antimony, etc. as a binder to mix with graphite to produce lead cores, which made a big step forward in pencil manufacturing technology. From 1790 to 1793, the French NJ Kant used the method of washing graphite for the first time to improve the purity of graphite, and used clay to bond the graphite to make a pen core. This method is called Kant’s method. The Kant Pencil Factory was established in 1793, which laid the foundation for the modern pencil industry.China established its first Dahua Pencil Factory in Kowloon, Hong Kong in 1932. Subsequently, the Beiping China Pencil Company and the Shanghai Huawen Pencil Factory were successively built, both of which were semi-finished products processing plants. In 1934, the China Standard Domestic Products Pencil Factory was established in Shanghai, and began to make lead cores and began to study the use of domestic raw materials to make pencils. After the founding of the People’s Republic of China, large-scale pencil factories with an annual output of 150-250 million pieces have been successively built in more than 10 cities including Harbin, Beijing, Tianjin, Jinan, Dalian, Fuzhou, Shenyang, and Bengbu. Lead-core manufacturing, paint and printing decoration technology have also been continuously improved, and all-plastic pencils, resin fine-lead cores and fine-core mechanical pencils have been developed. Developed into new equipment such as glue board bundle clamp dryer, automatic painting machine, electric tunnel core burning furnace, board laying machine and various packaging machines.
The materials for pencil shafts mainly include wood and glue. Wood is used to make penholders. It requires straight texture, fine and uniform structure, soft or slightly soft, slightly brittle, less resin, low moisture absorption, small expansion and contraction, and no deformation. There are mainly pencil cypress (red cedar), cedar, Sida wood, basswood, alder and so on. The adhesive should have proper viscosity, fluidity and wettability. After hardening, the adhesive layer has toughness, has little damage to tools, has certain water resistance, heat resistance, and aging resistance. It is easy to solidify at room temperature, has a short hardening time, and is non-toxic. Mainly include animal glue, polyester acid vinyl emulsion, hot melt glue and so on.The raw materials of graphite lead core and auxiliary materials are graphite and clay. Graphite is a coloring agent. With its smoothness and plasticity, a lead core can be made to draw black marks, firmly adhere to the surface of the paper, and can be erased with an eraser. Graphite with high carbon content and fine particles should be selected. Clay acts as a binder, and uses its plasticity and cohesiveness to bond graphite particles together. It requires clay with good plasticity, low iron content and wide sintering range. Auxiliary materials include molding materials and materials that change the performance of the lead core. Molding materials are used to improve plasticity and adhesion, and improve the molding performance of lead cores. Commonly used are caramel, gum tragacanth and so on. Changing the performance of the lead core material is used for the oil immersion treatment of the lead core after sintering, so as to improve the physical properties of the lead core (such as abrasion, concentration, force on the core tip, slip, hardness, etc.). Commonly used are paraffin, tallow, petrolatum, etc., usually two or more of them are used in combination. The color lead materials include pigments, physique materials, adhesives, greases and waxes. Pigments (including pigments and dyes) play a coloring role, requiring good tinting power, high hiding power, soft quality, high fineness, good heat resistance, and non-toxicity. Commonly used are titanium dioxide, carbon black, phthalocyanine blue and so on. Physique raw materials play the role of bonding, skeleton and adjusting hardness.
The classification of the pencil models we use today is based on the hardness of the pencil. The harder is H (hard, hardness), and the softer is B (black, the depth of black): 12B-B, HB, H-12H. The “B” type pencil has a large graphite content and a small clay content. The larger the number in front, the thicker and softer the pencil, and the deeper; the “H” type pencil has a large clay content and a small graphite content. The larger the number in front, the thinner and harder the pencil, and the lighter it will be. The HB pencil is a half lead core of clay and graphite. There is also a pencil marked “F”, which is the first letter of the English word firm (firm), indicating that the hardness and blackness are between HB or B.
The use of pencils should be based on the appropriate model. For example, the pencil used for writing is “HB”, the drawing and sketching generally use “8B” or more, and when filling out the answer sheet, use “2B”.Generally speaking, the model range of pencils we use when drawing is 6H-8B. Usually “HB” is used as the basic model for drafting and paving the tone, because “HB” is moderately soft and hard, not easy to scratch the paper (hard lead), or too deep to be conducive to the “color gradation”, so that the picture is too dirty (soft lead) ). The use of soft lead and hard lead must be moderate and suitable for local conditions. In addition, factors such as whether the paper is “leaded” should also be considered.
The correct use of pencils will bring better expressiveness and artistic atmosphere to our pictures.