CHAPTER III
METHODS OF PRINTING
IT will be the aim of this chapter to show how to make really good and permanent impressions of the fingers. It is very easy to do so when the principles of the art are understood and practised, but difficult otherwise.
One example of the ease of making good, but not permanent impressions, is found, and should be tried, by pressing the bulb of a finger against wellpolished glass, or against the highly-polished blade of a razor. The finger must be very slightly oiled, as by passing it through the hair ; if it be moist, dry it with a handkerchief before the oiling. Then press the bulb -of the finger on the glass or razor, as the case may be, and a beautiful impression will be left. The hardness of the glass or steel prevents its surface from rising into the furrows under the pressure of the ridges, while the layer of oil which covers the bottom of the furrows is too thin to reach down to the glass. or steel ; consequently the ridges alone are printed. There is no capillary or other action to spread the oil, so the impression
