Engraved printing is traditional for formal stationery, such as wedding invitations and business cards, because of its rich, elegant appearance.
In engraving, stationery is pressed onto an engraved copper plate, which causes the printed letters to rise slightly off the page. Hence, "raised ink."
In thermography, the design is printed on the sheet and the sheet is then passed under a powder funnel that sprinkles a powder-like substance on the sheet. The sheet is then passed under a heated oven that fuses the powdered particles to the wet printing ink, and a high-powered vacuum is used to remove the excess powder. The fused mixture creates the "raised" appearance when the mixture hardens.
Thermography produces the effect of engraving without the expensive, time-consuming engraving process, making the traditional effect affordable.
Raised ink printing requires the use of materials specially designed for the technique, or problems can occur, such as the curling of paper, because of the high temperatures used in the process.