4c Columbian, Error of Color
(233a). Slightly disturbed original gum, deep rich color in the more
intense of the two error shades, fresh and bright paper, wide
marginsFINE EXAMPLE OF THE RARE 4-CENT COLUMBIAN ERROR OF COLOR.
The 4c Columbian color error was caused by the use of a wrong batch of ink, and spectrographic analysis has shown that the blue inks of the 4c error and 1c Columbian have the same components.
Stamps from at least two panes reached collectors, and the few cancelled examples indicate that stamps used by the public came from other panes. It is likely that a number of full sheets were printed using the wrong ink, and most of the stamps have simply been lost to philately. (Image)
4c Columbian, Error of Color
(233a). Beautiful deep rich color, light strike of duplex circular
datestamp, faint diagonal crease at top leftFINE APPEARANCE. ONLY THIRTEEN USED EXAMPLES OF THE 4-CENT COLUMBIAN ERROR OF COLOR HAVE BEEN CERTIFIED BY THE PHILATELIC FOUNDATION. ONE OF THE GREAT RARITIES OF USED UNITED STATES STAMPS.
Only four of the thirteen are sound, and two of the sound copies have not been re-examined for faults since the 1940's. Therefore, the number of sound copies may actually be less than four, and may only be two. Most of the used examples are also off-center to some degree, with eight having the perforations either close or touching on at least one side. In the last seven years, this is only the fifth used example of this rarity we have handled.
Unpublished Census No. 233a-CAN-10. With 1979 Friedl and 1997 P.F. certificates. In our opinion, this is undercatalogued in Scott given its rarity compared to unused copies. (Image)
8c Columbian, Right-Reading
Impression on Back (236 var). Original gum, h.r., clear impression,
Fine, from the sheet that generated so much controversy over the 8c
"Printed on Both Sides" -- some arguing it is a secondary offset (right
reading), others claiming that it must be a double printing -- unlisted in
Scott, with 1982 P.F. certificate as "genuine printed on both sides
variety" (Image) 
$4.00 Columbian (244).
Original gum, barely hinged, deep rich color, choice centering with
enormous marginsEXTREMELY FINE GEM. A HUGE ORIGINAL-GUM EXAMPLE OF THE $4.00 COLUMBIAN ISSUE.
With 1993 P.F. certificate (Image)
$5.00 Columbian (245).
Bottom sheet selvage with plate no. 108 and part imprint, perfect
strike of "Mount Savage Md. Dec. 30, 1893" circular datestamp, slight
crease and small thin, Very Fine appearance, unusual and ideally suited for
exhibition (Image)
4c Columbian (233). Bottom
imprint, plate no. 20 and "D" block of ten, original gum, barely hinged,
bright color, few expertly reattached perf separations, Fine (Image)
5c Columbian (234). Top
imprint, plate no. 9 and "B" block of eight, original gum, hinge slivers
causing tiny gum soak, rich color, Very Fine
(Image)
6c Columbian (235). Bottom
imprint, plate no. 104 and "Z" block of eight, brownish original gum,
lightly hinged, few minor perf separations, otherwise Fine (Image)
10c Columbian (237). Top
imprint, plate no. 99 and "Y" block of eight, brilliat color and crisp
impression, original gum, barely hinged where few minor perf separations
expertly reattachedVERY FINE. A DESIRABLE TOP SELVAGE IMPRINT AND PLATE BLOCK OF EIGHT OF THE 10-CENT COLUMBIAN.
Scarce in such attractive condition (Image)
15c Columbian (238).
Bottom imprint, plate no. 58 and "M" block of eight, original gum, barely
hinged, deep rich color on bright paper, few trivial perf separations at
rightEXTREMELY FINE PLATE BLOCK OF EIGHT OF THE 15-CENT COLUMBIAN ISSUE.
Scarce in such pristine condition (Image)
30c Columbian (239). Top
plate no. 59 and imprint block of six, original gum, lightly hinged, deep
shade, unusually choice centering, selvage slightly reducedVERY FINE-EXTREMELY FINE IMPRINT AND PLATE NUMBER BLOCK OF THE 30-CENT COLUMBIAN ISSUE.
30c Columbian plate blocks from the desirable top positions are very scarce. (Image)