TABLE OF CONTENTS Liquid inks are more like paints as they are well pigmented/filled for color and opacity effects. They are usually viscous and contain either water or organic solvents. Therefore, the method of deformulating inks is similar to that of paintand coatings. Of course, inks are not paints and are formulated for printing, drawing, writing, and the like.
Sources of inks and methods ofpreparation are shown in Fig. 15.1. These solid specimens are scraped or cut from the substrate before proceeding with the deformulation. The specimen can be cut with a sharp razor blade or frozen in liquid nitrogen and broken to reveal a fresh surface. Also, the specimen can be pulverized to particles, swelled in solvent, and separated by centrifugation.
Figure 15.2 outlines a series of steps for complete deformulation of a solid ink specimen.
The exposed cross-sectional surface of the specimen is examined by optical and electron microscopy to determine the magnified appearance of the specimen. The specific magnification is left to the operator to resolve the image. The shape and size of particles are observed directly, and EDXRA determines the elements present in the particles and vehicle down to an atomic number of5.
Example. A magnified image of the author's initials written in black pen ink is shown in Fig. 15.3. The section of the "J" marked with an...
