Application of Colorants Inks

Two inks are submitted to a forensic chemist for comparison, one a dark blue and one a light blue. How would the chromaticity values be expected to differ  

Answer For the first part of the question, refer to the chromaticity space plot shown in the color insert The darker the color, the farther the point will be toward the periphery of the parabola the lighter the color, the closer to the center it will be. CIELAB values would be the best choice for expressing the color difference quantitatively. 

Solvents common in ink formulations (in addition to water) are methyl ethyl ketone (MEK), isophorone, and the glycol ethers such as ethylene glycol. 

The Vinland map (mentioned and shown previously in Chapter 5, Applying the Science 5.3) has been controversial from the day it surfaced in 1965. The map appears to show the outline of Canada and North America—no great surprise, except that the parchment on which the map is drawn has been dated to the period 1411-1468. This dating, calculated from C techniques, is not disputed. Columbus sailed to the New World in 1492, but Vikings had discovered and settled in North America hundreds of years earlier, another fact not contested. However, the authenticity of the map has been questioned on the basis of the ink and techniques used to create it. Modern forgeries created on old parchment arc not uncommon, but it is difficult to forge the types of pigments that would have been used on an authentic map. This is the heart of the controversy. 

The map was donated to Yale University in 1965, and at the request of the university. Dr. Walter McCrone, the famed microscopist and chemist, examined it. Using PLM and other techniques, he concluded ffiat a clever forger had first drawn a yellowed outline on the paper with a yellowish 

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