Paper size a number of different sizes were defined for large sheets of paper, and paper sizes were defined by the sheet name and the number of times it had been folded. Thus a full sheet of "royal" paper was 25 × 20 inches, and "royal octavo" was this size folded three times, so as to make eight sheets, and was thus 10 × inches. Imperial sizes were used in the United Kingdom and its territories. These sizes are no longer commonly used since the UK switched to ISO sizes. Many of these sizes were only used for making books (see bookbinding),
Folded leaflet Also known as a spiral fold, tri fold, brochure fold, business letter, C fold, roll fold and barrel fold. Also known as a window fold. In double parallel folds the paper is folded in half and then folded in half again with a fold parallel to the first fold. To allow for proper nesting the two inside folded panels are 1/32" to 1/8" smaller than the two outer panels. In double gatefolds there are three parallel folds. The left and right edges of the paper fold and meet in the middle, without overlapping, along a center fold. The outer panels