IRC - see International Reply Coupon.
IRT - see Integrated Retail Terminals.
Illegal Use - an illegal use of a stamp, such as a revenue stamp used in an attempt to pay postage.
Image Tagging - the tagging of only the image (design) or a portion of the image on a stamp. Examples: 1988 25¢ Classic Autos (Scott 2381-2385); 1999 33¢ American Glass (Scott 3325-3328).
*Imperforate - stamps without perforations. The earliest stamps were issued in imperforate form. Imperforate stamps that were intended to be perforated are errors.
Imprint - any information (except a plate number) printed in the margin of a sheet.
Imprint Block - a margin block of stamps, analogous to a plate block, which contains an imprint instead of a plate number.
India Paper - a soft, tissue-like paper used for making die proofs.
Indicia - plural of indicium.
Indicium - 1.) the stamp-like impression on postal stationery, 2.) the imprint of a postage meter.
Ink-Jet Cancel - a dot matrix cancel also known as a Sprayed-on Cancel.
Insured Mail - mailed articles insured for a fee by the Postal Service.
*Intaglio - a process of printing from the recessed portion of a printing plate. see also Engraving
Intagliocolor 8 Press - high-speed, three-color, sheetfed intaglio press used at the BEP from 1976-1985.
Integrated Retail Terminals - Computers in post offices that weigh items, calculate postage, print receipts and maintain records.
Interleaves - sheetlets of glassine paper used to separate panes in stamp booklets.
International Envelope Corp. - manufacturer of early and mid-20th century stamped envelopes and wrappers.
International Mail - mail sent from the United States to a foreign nation or sent from a foreign nation to the United States, as opposed to Domestic Mail.
International Philatelic Exhibition - one in a series of once-per-decade international stamp shows hosted in the U.S. Held in New York City in 1926. The Battle of White Plains stamp and souvenir sheet were issued in conjunction with this show. (Scott 629 & 630.)
International Postal Supply Co. - major manufacturer of cancelling machines in use from the 1880s to the 1990s.
International Reply Coupon - a coupon sold by the post office that is redeemable by its recipient in a foreign country for return postage. Scott catalogue numbers begin with IRC.
International Vending Machine Company Perforations - perforations privately applied to imperforate flat plate stamps by the International Vending Machine Company for use in its vending machines.
Interphil '76 - one in a series of once-per-decade international stamp shows hosted in the U.S. Held in Philadelphia in 1976. A stamp was issued to honor Interphil '76. (Scott 1632).
Interrupted Mail - mail that has been delayed by some external event such as a plane or train crash, war, fire, etc.
*Invert - a stamp or item of postal stationery on which one portion of the design is upside down in relation to the rest of the design. Inverts can only be produced when the production process requires at least two independent passes through a press. Inverts are errors.
Inverted Jenny - nickname for the 24¢ air mail error stamp of 1918 on which the airplane (vignette) was printed upside down in relation to the frame. Scott C3a.
Irradiated Mail - mail irradiated by the U.S. Postal Service during the anthrax terrorism of 2001-02.
Italian Occupation Issues - see Allied Military Government Stamps.
Jeffries Banknote Co. - subcontractor to American Banknote Co.. for the 1991 $14 postage stamp (Scott 2542).
Jenny - see Inverted Jenny.
Joint Issue - stamps issued by two or more countries simultaneously, with similar designs, honoring the same person or event. Example: 1975 Apollo-Soyuz Space Issue, Scott 1569-70.
Joint Line - the printed line produced on the web by the rotary press at the point where two plates met. Two plates were used in combination with each other on the classic rotary press. Each plate would fit over half of the printing cylinder. Ink would gather in the joints between the plates, leaving an impression - a joint line - on the web. One complete revolution of the press cylinder created two joint lines on the web. Joint lines were produced on both sheet and coil stamps, but only those produced on the coil stamps are commonly collected. A Joint Line is NOT the same as a Guide Line.
Joint Line Gap Pair - A joint line pair of precancelled coil stamps that shows the gap between the auxiliary plates used to print the precancel.
*Joint Line Pair - a pair of coil stamps produced from the rotary press with a joint line between them. A joint line pair will contain one stamp from each of two different plates. See Joint Line.
Junk Mail - nickname for advertising send by bulk rate mail.
K - prefix letter used by KCS Industries in front of the plate number on its modern stamp production.
KCS Industries - private printer and finisher of postage stamps. Worked in partnership with several other companies. Example: non-denominated Tulip booklet of 1991 (Scott 2520).
Kansas City Roulettes - home-made perforations applied by roulette to imperforate 1¢ and 2¢ postage stamps (Scott 408 and 409) by the postmaster of Kansas City in 1914 and 1915.
*Kansas-Nebraska Overprints - Fourth Bureau Issue postage stamps overprinted Kans. or Nebr. in 1929 for sale in those states, but valid in all states. Scott 658-679.
Killer Cancel - a cancellation that is very heavy, obliterating most of the design of a stamp.
Knife - 1.) the pattern used to cut an envelope from a sheet of paper. 2.) the device that cuts stamps apart as they are fed through an affixing machine.
LL - Lower left. Refers to the lower left pane from a traditional sheet of four panes. These initials are also used to describe plate blocks taken from the lower left corner of such sheets.
LR - Lower right. Refers to the lower right pane from a traditional sheet of four panes. These initials are also used to describe plate blocks taken from the lower right corner of such sheets.
L perforator - an L shaped manually fed perforating machine on which stamps receive horizontal perforations on one leg of the L and vertical perforations on the other.
Label - a stamp-like adhesive of no postal value, often used for promotional purposes. Christmas Seals are examples of labels. "Label" may also be used to describe the stamp-like units that bear messages that sometimes appear in stamp booklets.
Large Banknotes - postage stamps produced from 1870-1888 by the National, Continental and American Banknote Companies. Scott 134-218. See also Small Banknotes.
Large Die Proof - a die proof printed on card stock that is considerably larger than the image created by the die, as opposed to a Small Die Proof. The die print on a Large Die Proof is located in a recess on the card known as a sinkage.
Late Fee - payment required for mail accepted for dispatch (usually on a particular ship) after the closing of the mails.
Laundry Tags - two-sided address cards used on suitcase-like containers (mostly by college students) to mail dirty laundry home to be cleaned and returned.
Layout Marks - dots, lines and arcs that are scribed by a siderographer on a blank plate to determine the precise location for each entry to be made from the transfer roll.
Leader - a strip of brown kraft paper (white paper beginning in 1948) attached to the leading (first) stamp on a roll of coil stamps.
Leavitt, Thomas - major manufacturer of cancelling machines in use from the 1870s to the 1890s.
Legends of the West - a pane of twenty stamps that was recalled because an incorrect picture appeared on the stamp of Bill Pickett (Scott 2870). A limited number of recalled panes was sold by public lottery. The corrected version (Scott 2869) was then printed and issued.
Letterpress - a process of printing which is the exact opposite of intaglio, that is, the inked portion of the plate is raised above the surface of the plate, as opposed to be being recessed below it. Letterpress (also see typography) has been used to print overprints on US stamps. It is also used in perfecting (back printing) inscriptions on the gum of many stamps, and to print most modern stamped envelopes.
Letter Sheet - see aerograms.
*Liberty Series - definitive series of postage stamps appearing in 1954, consisting of sheet stamps, coils and booklets. Also known as Sixth Bureau Issue. First Scott number is 1030a.
Library Mail Rate - special rate for mailing certain materials to or from certain non-profit organizations, a sub-category of Package Service. Commercial libraries could also use this rate as long as the contents were suitable (books, motion pictures, etc.).
Line Engraving - see Engraving.
Line Gaps -the gap between plates printing precancels that appears on coil stamps at regular intervals.
Line Pair - see Joint Line Pair.
Liner - slick paper used as peelable backing for self-adhesive stamps.
Linerless Coil - self-adhesive coil stamps sold in a roll without a liner. Example: 1997 32¢ Flag over Porch stamp, Scott 3133.
Lithography - printing from a flat surface on which the area that is not to be printed repels the ink. One form of lithography is direct lithography, in which printing occurs without the use of an intermediate roller or blanket. Some early Post Office Seals were printed from such direct lithography. Indirect lithography uses an intermediate roller or blanket, and is called offset. see Offset Lithography.
Local Post - a private postal system operating in a limited area, usually a major city. Local posts once played a significant role in mail delivery.
Local Precancel - a precancel applied to stamps locally, as opposed to being applied at the Bureau of Engraving and Printing. see also Bureau Precancel.
Local Stamps - stamps issued by a Local Post. Scott numbers begin with L.
LOOK Coil - phosphor tagged version of the 3-cent Statue of Liberty coil in the 1954 Liberty Series, issued unannounced in October 1966 for use on LOOK Magazine promotional mailings. Use by LOOK Magazine was limited to about a six month period, after which the stamps were recalled, marking the first time the U.S. Post Office Department bought stamps back from the private sector for distribution to collectors. Tagging applied by rubber mats and glows brightly under ultraviolet light. see also LOOK Coil Reprint.
LOOK Coil Reprint - a special printing of the LOOK Coil made to satisfy collector demand. The reprint became a new variety because the BEP applied the tagging by metal plates. The tagging on the reprint glows duller and grainier under ultraviolet light than the tagging on the original LOOK Coil.
*Louisiana Purchase Exposition Stamps - commemorative postage stamps issued for the St. Louis Exposition of 1904. Scott 323-327.
Lozenges - the bi-colored border frequently found on air mail postal stationery.
Luminescence - the effect given off by fluorescent brighteners and phosphorescent tagging in paper and ink when activated by ultraviolet light.