Pigment, extenders that bulk out the lead, binders and water go into a large mixer and are worked into an even dough. Every shade has its own recipe, and one Swiss maker keeps more than 400 colors.

The dough is rolled into flat sheets, and machines press the sheets into thick solid cylinders called cartridges. They stay damp and pliable for the next step.

An extrusion press forces each cartridge through a small tube the width of a finished core. A continuous colored rope comes out, and an automatic slicer chops it into pencil-length pieces.

Fresh leads are too wet to handle, so they go into large ovens until they are hard enough to set into wood.

Baskets of cooled leads sit in melted wax for a full day, which softens how they lay down color. Sample leads are then snapped to measure their breaking force, and ten more each write 10 meters to test wear.

Debarked lumber is milled into slats about as long as a pencil and about three inches wide. A second milling machine cuts small half-round grooves down each slat at regular intervals.

A machine drops one lead into each groove, spreads glue, and lays a second grooved slat on top. The sandwiches are clamped tight and stored until the glue sets.

Another milling machine slices through each glued block between the leads. Depending on the design, the cutters leave round or hexagonal pencils.

Pencils pass through paint or varnish, often in the same color as the core. At one factory each pencil gets 6 coats, riding more than 40 meters of drying belt after every coat. Hot stamping adds the brand and color number, and a blade or abrasive strip cuts the point.