Page 22 - Charles Shreve - William H Gross United States 1847 Issue

D. Deliveries and Shades Introduction

In each delivery many shades exist.

The brown color selected for the stamp was obtained by mi.xing several ink pigments. A formula existed but the tolerances
were quite liberal. In addition, environmental issues, measurement of quantities and adjustments during each printing
could account for many of the shades. The very rich shades originate from inks that would concentrate in storage or from
ladling the bottom of the pigment container.

Early impression. Late impression.
Dark brown with red tint. Orange e

tffac,-/ ;#.-(?ff~7

~,4c_~ /2'.

Cinnamon brown - SE 22, ?? to Erie, P A

New shades.

Previous students limited their color nomenclature to 15 shades although admitting that there were more slight
shades and tints. The colors in this exhibit are identified with the aid of Robert Ridgway's Color StandardJ and
Nomendature and derive from the seminal work of\V'ade Saadi.

Reason for the change of impressions between printings.

The dyestuffs in the ink formula used for the 5~ were composed of elements that were abrasive to the printing
plate. Brown inks, in particular, contained metal oxides that could wear down the fine lines of the engraved plate.