This stamp comes in the famous "blue
paper" variety, although quite rare and unlikely to show up in an
unchecked mixture of Washington Franklins. The "blue" is actually
a "gray color", not really "blue", but it may take
on a slightly bluish tint. The stamp was made with a higher percentage of
rag content (about 30%) resulting in a grayish tinge to the stamp. As a
first check, be certain the stamp is double-line watermarked, all "blue
papers" are double-line watermarked. Fortunately, double-line
watermarks are hard to miss, if you don't see one the stamp is suspect. If
you think your stamp is the "blue paper" variety, you MUST have
this stamp certified. Even faulty, poorly centered examples of this stamp
command a premium far in excess of the certification fee. If the stamp is
genuine, it will retrieve a far higher price when certified. Conversely, do
not purchase a non-certified copy of this stamp. If the seller is unwilling
to pre-certify the stamp, there is a high likelihood that the genuineness of
the stamp is in question.
