请输入您要查询的百科知识:

 

词条 crayon
释义
crayon
an implement for drawing made from clay, chalk, plumbago, dry colour, and wax. There are two types of crayons, the colouring crayon and the chalk crayon.
The colouring crayon, or wax crayon, is the one used by most children in making pictures, but artists also use it. It consists of waxes such as paraffin, beeswax, and carnauba wax and dry colour. Some synthetic waxlike materials are also used in the modern crayon. The waxes are melted and the dry colour added with continuous mixing until thoroughly dispersed. Normally, the crayon is entirely consumed during the marking process through abrasion.
The blackboard crayon, or chalk, that is used in classrooms is commonly composed of calcium carbonate, kaolin clay, oleic acid, and caustic soda. Dry colour may be added to increase the whiteness or to impart specific colours. Modifications of the formulation, such as mixing pigment with a nongreasy binder as with pastels, have provided chalk crayons for more specialized use by artists, tailors, and carpenters. For lithographic (lithography) prints a plain dark-coloured crayon made of wax, soap, lac, mastic, sheep tallow, lampblack, and sometimes copal is used to draw an image directly on the stone surface. See also conté crayon; lithography; pastel.
随便看

 

百科全书收录100133条中英文百科知识,基本涵盖了大多数领域的百科知识,是一部内容开放、自由的电子版百科全书。

 

Copyright © 2004-2023 Newdu.com All Rights Reserved
更新时间:2025/2/20 3:16:26