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Mean Weighted Fiber Length. American 1879 20. American 1879 26. American 1879 27. 63.6 mm 2. Technidyne Profile Plus instrument. National BNC Stamps Oil Gurley Porosity. The higher the number, the lower the porosity. Continental BNC Stamps Oil Gurley Porosity.
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Mean Weighted Fiber Length American 1879 20 American 1879 26 American 1879 27
63.6 mm2 Technidyne Profile Plus instrument
National BNC Stamps Oil Gurley Porosity The higher the number, the lower the porosity
Average Oil Gurley Porosity of Stamps American 1879 American 1881 National Continental
CIELAB values of stamps L - a +a National - large squares; Continental - large circles; American 1878 - small squares; American 1881 - small circles
Eab Color Difference Average CIELAB vs. Designated Color National Continental Am. 1879 Am. 1881
Conclusion • Analyses of bending index, fiber length, and porosity showed that all three companies used different types of paper, and that more than one paper was used by each company • National and Continental both used two discrete types of papers. • Three different papers were used by American in the 1879 printing. Their 1881 re-engraved stamps were printed on two different papers.
Conclusion • Green as described by the Scott catalogue is different for every manufacturer. • The average CIELAB value of National stamps shows a Eab = 3.4 color difference from National“Green”. • Continental’s average stamp has a CIELAB value of 47.5, -23.8, 7.5 and its color difference from Continental “Green” is Eab =3.0. • American 1879 has a Eab 4.6 from American 1879 “Dark green”, and American 1881 has Eab=1.8 from American 1881“Green”.
a.pekarovicova@wmich.edu Thank you!