What is the lead and what are its unique properties for drawing?
Grifel (from German) is a stick for writing,a core of a kind of shale, designed to write on surfaces of slate. What is a pencil in the modern sense? This is the same as "graphite", writing the pencil rod.
Properties of graphite
The pencil pencil is made of graphite,which is a form of natural carbon. Graphite under the influence of pressure and heating in the soil acquires a crystalline structure. Its crystals resemble plates, united by a weak connection.
The most common type of graphite is amorphous, or slate, a crystal. It is known that such a griffin differs in friability and is not suitable for drawing.
About 1500 years ago in England was discoveredgraphite of high density, where it was subsequently mined for three years. Graphite, corresponding to the description, was used in the manufacture of gunner molds.
Quality graphite contains a high percentagecarbon. In addition, it turned out that the lead of such a property has in its composition the largest share of clay. Thanks to the clay, the mixture maintains its strong consistency until the moment of calcination, and after it has a cementing effect.
Production of pencils
The manufacture of pencils was improved onthroughout the XVII century. Graphite was cut into thin sheets. Such a rod was placed in a wooden rack, which was covered with another similar rod, and as a result of gluing together the two halves, a pencil was obtained. It was sharpened from one end and with the help of a plane was given a rounded outline.
In 1795 the French chemist N.Conti created the formula of a graphite rod. It consisted in the fact that a griffon of the type "amorphous" was combined with clay and it was subsequently fired prior to conversion to a solid consistency. Currently, the formula has remained relevant for the manufacture of pencils.
For the lead to be suitable for writing ordrawing, it is impregnated with wax. When the graphite is immersed in the wax mass, air bubbles appear on the surface as a sign of waxing the space filled with water in the extrusion process.
Technique of drawing
Pencil - universal and very convenienttool in the hands of the artist. With its help you can create sharp, clear, soft and refined lines, erase them and apply again. By adjusting the pressure, it is possible to create a tonality on the periphery of the entire pattern and its outline.
Color pencil is susceptible to the surface of the baseto apply the image, so the stroke on the smooth paper differs from the stroke on the rough paper. Color pencils are made standard and water-soluble. White spirit dissolves the wax in the pigment of the stencil pencil, and this property can be used for various effects. A water-soluble pencil is more predictable and safe to work with, so it is used for the usual stroke and fill effect.