The articles necessary are a special ink described below, a stub pen, lead filings and a small blank card.
The ink is made by dissolving one part of liquid glue in five parts of water and adding sufficient carbolfuchsin or other dye to color it. The lead filings are made by filing metallic lead with an ordinary 8 inch steel file; one even finer is better.
The name, date, part to be photographed or other data required are written on the blank card in a round, plain, heavy script. The card is covered with the lead filings while the ink is still wet, and let stand for a moment. The filings which are not held by the glue in the ink are shaken off, and the card is ready for use. The card is laid on any convenient part of the plate while the plate is being exposed. When it