This sheet of decorated paper is of size B2 ~ 500x707mm. It has been folded twice, and then unfolded. That leaves four equal shapes each of size B4. The fingertips are designed to give some idea of the scale. The paper is a fantasy of coloured feathers ~ printed by Rossi 1931, of Italy. In practice very often sheets ~ such as this are ~ are finished at 50cmx70cm, although it should be 50x71cm.
This is the size at which most retail shops sell decorative wrapping papers such as this. The folds are normally there to enable transit and storage. B2 is quite a large size to handle when not folded or rolled.
Carriage costs are signifcant on papers such as this, even when a B2 sheet is creased twice to B4 ~ which is the exact size of a large letter, meaning that there is no allowance for the envelope or wrapping.