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dry media consist of natural or synthetic mineral or plant substances that
deposit crystalline or splinter-like fragments in the paper fibers. Natural
chalks. contained their own binders in the form of clay. Charcoal has none.
Artists or manufacturers also sometimes added binders. When stroked against
the surface of the paper, they deposit fragments in the upper fibers. Consequently
they lend themselves more or less easily to erasure and correction. In this
way they provide the draftsman with flexibility in his initial inventions. |
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