The Post Office Departmental Stamp Designs of 1873

The 1¢, 3¢, and 6¢ stamps were printed on plates of 200 stamps and cut into two panes of 100 stamps
The 2¢, 10¢, 12¢, 15¢, 24¢, 30¢, and 90¢ stamps were printed on plates of 100 stamps
Perforated 12 - Issued July 3, 1873 - Printed by the Continental Bank Note Company on "thin, hard" whitish paper

Scott O47
1¢ Post Office
Scott O48
2¢ Post Office
Scott O49
3¢ Post Office
Scott O50
6¢ Post Office
Scott O51
10¢ Post Office

Scott O52
12¢ Post Office
Scott O53
15¢ Post Office
Scott O54
24¢ Post Office
Scott O55
30¢ Post Office
Scott O56
90¢ Post Office

The Post Office Officials range in color from gray black to black. The 3¢ Post Office Departmental stamp was also issued in 1879 by the American Bank Note Company on soft porous paper. The stamps are distinguished by paper type, the Continental stamps are on thin hard paper and the American stamps on soft porous paper:

see: Bank Note Paper Types

Three Cent Post Office Official
Scott O49 - Continental Bank Note Printing of the Post Office Department 3¢ stamp
Scott O108 - American Bank Note Printing of the Post Office Department 3¢ stamp