Pieters & Co., 4¢ Black, Experimental Silk Paper, bold color and crisp impression, usual light vertical creases and some scissor separations, Fine appearance, still a handsome example of the Pieters & Co. 4¢ Black on Experimental Silk Paper, A Great Rarity With Only 8 Examples Recorded in the Aldrich census (of which half are reported to be faulty). Scott No. RS191e  $5,000. $0 (Image)