Modern scratchboard was developed in the late 19th century to meet the demand for illustrations for the rapidly proliferating books, newspapers, magazines and advertisements. Wood engraving was widely used to reproduce paintings and photographs for printing, but it was time-consuming and required working in reverse.

Several versions of cardboard coated first with chalk, then with India ink, were developed in England, Austria and Italy. Fine lines could be scraped or scratched through the ink, simulating wood engraving. These new materials eliminated the need to work in reverse, were easy to correct, and allowed artists to work on a larger scale, as the fine linework of scratchboard art could easily be photographically reduced for reproduction.

Scratchboard was widely used for advertising and editorial illustration from the 1920s to 1950s and has seen something of a renaissance in the last two decades. Scratchboard’s graphic impact, subtle shading possibilities, and ease of use make it a very appealing medium.

Materials Needed: One of the great things about scratchboard is the minimal amount of supplies needed. For many years, I used English scratchboard, which consists of a cardboard base covered with a thick layer of white chalk made from crushed eggshells. This white surface may be painted with black and/or colored ink, which is then scratched through to etch your picture. I am currently using a black-coated scratchboard made in Texas. It is called “Claybord”, and it is made of Masonite onto which the chalk is deposited. Both types of scratchboard provide a very thin coating for easier and cleaner scratching.

High quality scratchboard can be finely cross-hatched and will not flake. Less costly boards use thin cardboard, and due to their thinner chalk coating, a scratching tool will often penetrate to the cardboard, resulting in a ragged, rough picture.

Most art stores stock a sharp-pointed scriber for line work and a spoon type for wide, clean and quick removal of the black surface. I prefer a needle type, which I originated. I use a common straight pin, like you might use in sewing, and put it in a holder. Any holder will do. I have found that a common straight pin is better than any tool. You never have to sharpen it, and it works perfectly from the start. When it gets dull, you replace it. And, using straight pins are very reasonable; you can get hundreds for just a few dollars. A straight pin is easier to handle than most tools and it makes finer and more accurate lines and makes curves and circular motions more easily. I use my needle scriber and the spoon-type scriber exclusively.

The Basic Technique:

• First, make a preliminary pencil drawing on a fairly thin paper, such as tissue paper. Once you have made a satisfactory pencil drawing, tape your drawing to your scratchboard. If you are using the English scratchboard, trace your drawing with a ballpoint pen to indent the board. When the drawing is removed, the traced lines will show on the scratchboard as grooves or indented lines . If you are using the Masonite-type scratchboard, use white carbon paper under the sketch and trace the sketch with a ballpoint pen. This will leave a transferred white image onto the board.
• After tracing with the pen, remove the taped drawing and scribe the grooves to outline your picture. The lines will show where you’ve traced, preventing duplicated traces and providing a good outline to follow. The scribing of these indentations make the outlines of the drawing more easily visible.
• The indentations can be seen with good lighting. Your pencil drawing will act as your blueprint. Using the spoon scribe, remove all black areas that are shown to be white on your drawing. Personally, I prefer to not clean white areas completely, but to leave remnants of the black in thin, sparse streaks, like a woodcut. This adds texture and looks more interesting than plain, solid white.
• After the white areas are established, do line shading for gray areas and cross-hatching in brighter areas. Continue to remove the black ink surface by scratching and shading to complete the picture. Remember to frequently look at your picture from a distance, so your composition will appear balanced.
• Now you will have a finished black and white picture which you can frame as is . . . or go on to color it.

Mistakes: Mistakes can be easily corrected using black India ink to cover areas with unsatisfactory linework. Once dry, the India ink can be rescratched.
 
Coloring the Scratchboard: If you decide to color the scratchboard, do not use acrylics, watercolors, or oils. These have too much opacity and will be visible on the black surface, besides covering up your textured scratching. I have found that transparent, fadeproof inks, such as the Dr. Ph. Martin brand inks, work best. I prefer to use Dr. Ph. Martin and Hydrus inks, both made by the same company. Be careful to read the labels — some are opaque. Coloring will diminish your highlights, so to bring them back, do some additional scratching with the spoon or needle to remove the color and reveal the white chalk.

Information provided by: http://www.getyourwordsworth.com