25c 20th Universal Postal Congress, Souvenir Sheet, Dark Blue & Gray Engraved Omitted (2438e). Mint N.H., vivid colors missing the Dark Blue "USA" and denomination, as well as the Gray title at top, fresh and strikingVERY FINE. ONE OF ONLY TWO RECORDED EXAMPLES OF THIS SOUVENIR SHEET COLOR-MISSING ERROR. A GREAT RARITY OF MODERN ERROR COLLECTING.The Datz book records only two examples of this error. Accompanied by a block of four of the similar perforated color missing error (No. 2437b, Scott Re