Violin bow ribbon width
Is there a standard width for the violin bow's ribbon? If I used a wider ribbon (and more hair), would I produce more sound?
I agree it is safer (for the violin edges) to fill the full width of the frog ferrule with hair. However, some soft sticks might require that be done with a very thin hair ribbon and a very thin hair ribbon, played on the edge, is likely to be harder on the edge hairs, breaking them faster than a narrower ribbon that does not fill the ferrule.
Everything Andrew said is great info, however in general the "standard width" is the width of the entire ferrule, it is possible your wedge isn't holding and the hair could be clumping. Check with your shop. Vorin school ferrules outside dimensions are roughly 13mm, depending on the gauge of the metal the hair ribbon could be anywhere from 10 to 12 mm.
It is determined by the width of the ferrule and the width of the mortice at the head.