A down has a delicate shape like a flake. It consists of an almost invisible down core with down barbs soft as silk and endowed with delicate ramifications growing radiantly from the core. Down is a highly resilient material. For instance, if you compress a fistful of down in your hand and unhand them, the down will quickly develop and recover their original shape.
Down are lighter than feathers. Due to their three-dimensional structure they can trap large amounts of air in between. This property is measured and figured in fill power (filling volume).
Air-filled pockets are formed between the fine barbules of the down which protect from cold. Due to their capacity of providing “warmth without weight”, down are extremely suited for top-quality bedding products.
From experience, one single down weighs about 0.0025 g to 0.0045 g. Down show differences depending on the breed and the weight of the geese and ducks.
About 250 000 to 400 000 single down are required to obtain one kilogramme of goose down.
To obtain one kilogramme of eiderduck down, which are the most delicate and at the same time the lightest down, approximately 500 000 to one million of single down must be collected.
Valid terms and definitions for feathers and down have been stipulated in a standard (EN 1885).
Further information at DOWNAPEDIA:
Quelle
Verband der Deutschen Daunen- und Federnindustrie e.V.
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