Christine Gerstenberg, age 11, of Hellertown, Pa., for her question:

HOW IS OIL PAINT MADE?

A paint maker starts his job by putting a special combination of liquids called the vehicle into a large mechanical mixer that also contains some powdered pigment. Out comes a thick paste which is then put into a grinder, or mill, to break up the pigment particles and scatter them throughout the vehicle.

The mill has steel lined cylinders that contain pebbles or steel balls. As the cylinders rotate, the balls or pebbles spin and hit against each other, grinding the paint.

Next the ground paste goes into a tank where more vehicle, solvents and driers are added. Lead, cobalt and manganese salts are often mixed in to make the paint dry quickly. Next a tint is introduced and, after being strained through a felt bag or filter, the paint is ready for packaging.