Italians rate flours differently from anyone else. Tipo is used to describe how finely milled the flour is, while the W scale describes the flour's strength (ie how long it takes to rise, how hard it is to work). Many recipes want the cook to mix flours to achieve the desired strength:
W 280-350 is for egg pasta and breads (65%-75% hydration).
W 150-200 is for pizza (55%-65% hydration)
W 170 is for pastry
Talcum-soft farina tipo 00 grano tenero is the finest milled, similar to pastry flour in the US; it's also used for making cakes and breads. To make it easy for the bewildered baker, companies are selling it ready-mixed: the label may say 'panificabile' ('bread ready') for making ciabatta and focaccia; or it may say it's for pizza or for dolci soffici.
Tipo 0 is an all purpose flour, with more of the bran and germ in it; coarser still are Tipo 1 and Tipo 2 until reaching wholewheat flour, or farina integrale.
Other kinds of flour include:
farina dolce: chestnut flour.
farina gialla: corn (mais or granoturco) flour. Corn starch is maizena.
farina nera: buckwheat (grano saraceno) flour.
farina semolina di grano duro: durum wheat semolina, for making dried pasta (with the slightly rough surface, best for absorbing sauce).
Images by: Angelo Amboldi