A good bow has 4 characteristics that I can identify. The first is quality construction. The wood of choice is Pernambuco aka Brazilwood. It is noted for its color, its lightness and that it does not warp over time. If the maker of the violin bow makes the effort to use the best wood, the shaft of the bow is almost always six sided.
By lightness of the bow the reference is literally to the weight. Most high quality bows are in between 56 and 64 grams. This is a weight that good violinists find most comfortable. It is a standard in both modern and antique violin bows.
The other technical aspect is the balance of the bow. Most high quality bows have a silver or whale bone wrap just above the frog on the shaft for balance. It gives the bow a nice look as well.
The history of a bow seems to have a huge impact on reflecting quality and thus shows up in the pricing. Three of the names that are well know in the world of antique violin bows are Tourte, Lupot and W E Hill and Sons. Hill bows illustrate best what makes antique bows valuable. To this day the company is noted for producing the highest quality violin bows. Antique examples of these bows have little marks and symbols on the frog, on the shaft and under the tip that identify which employee made which part that was then assembled into the bow. There is a book that reports the complete history of who was employed by this company and what parts he produced from what year to what year.
Quality bows withstand the test of time. It is a fairly simple instrument that has one fatal flaw. It warps. A bow has camber, the natural bowing that maintains the tension on the horse hair. However, the vast majority of bows will warp laterally over time. By that I mean that when you put the frog to your nose and you look down the bow it will bend to the right or left a little bit or quite dramatically. Any warp of this kind reduces that value of a bow.
