Copying pencil Copying pencil A copying pencil, also indelible pencil or chemical pencil, is pencil whose lead contains a dye. The lead is fabricated by adding a dry water-soluble permanent dye to powdered graphite—used in standard graphite pencils—before binding the mixture with clay. Copying pencils were introduced in the 1870s and were originally marketed for copying documents, especially for making permanent copies of a permanent original. This was achieved by creating a hand-written document using a copying pencil, laying a moist tissue paper over the document and pressing down with a mechanical press. The water-soluble dye in the writing would be transferred
Mechanical pencil barrel of the pencil. This was the most common type in the earlier part of the twentieth century. Many of these have a locking mechanism one way to allow the lead to be pushed back into the pencil. A clutch pencil (or leadholder) tends to use thicker leads (2–5.6 mm) and generally holds only one piece of lead at a time. A typical clutch pencil is activated by pressing the eraser cap on the top, to open the jaws inside the tip and allow the lead to freely drop through from the barrel (or back into it when retracting). Because