FINGERBOARDS for UPRIGHT BASS: What's to know??
What are they made of? Ebony is the material most used for most upright bass fingerboards, though there are many woods that can be used as a substitute. One of the main reasons ebony has been the wood of choice is the hardness of the wood, so it can resist being worn by the strings. Other woods commonly used are rosewood, jatoba, and hard maple (see ebonized below). You'll find that pure black ebony has become more rare, and thus more expensive, so you'll often find ebony with brown and gray streaks in use on many instruments; some makers and players will use a black stain (see ebonized below) to even the appearance of the ebony. However, I got a used ebony fingerboard for my homebuilt EUB that had been stained; the striped ebony beneath the stain is quite beautiful.
What is an ebonized fingerboard? This has become a marketing word that usually means that hard maple or another wood has been stained black so it resembles ebony. As long as it is a hard wood (there are many variations of maple, a very hard variety must be used so it resists wear) it's no sin- my old Kay had a maple board for several years. However, as it wears, you may need to restain it for appearance's sake. There is a perfectly good reason maple isn't used without a stain or coating. Our finger oils get into the wood and turns it an ugly gray and black, as you may have seen on old guitar and bass guitar maple fingerboards where the finish has worn off.
My fingerboard has dents and grooves from playing- what should I do? Fingerboards should be serviced every so often, usually when the wear impedes play. An experienced luthier can plane the board to make it smooth again. Eventually a board will become too thin to plane; that's when it's time to replace it. It's not uncommon, the fingerboard is a wear item that is simply a part of normal maintenance. That said, depending on activity, string abrasiveness, etc., it can take quite some time before a board needs surface work or replacement.
What if I want it to be deep black color? There are stains used for creating more uniform blackness that may have to be reapplied periodically. Aniline dye is one, but I like the black dye that is typically used by leather workers to stain belts, etc. That's not the stuff you'll find in a shoe store, but it is otherwise easily obtainable, search the web for a source ("fingerboard stain").
My fingerboard isn't flat, it's curved - do I need to fix that? No. If you lay a yardstick lengthwise against the board you should see daylight in the middle. "Relief" is the term used for the concave curve that is purposely cut into the fingerboard, to allow strings to vibrate without hitting the fingerboard. Unlike most bass guitars and similar instruments that have adjustable truss rods, the relief is planed into an upright bass fingerboard. This is necessary to avoid getting buzzing from undesired string/fingerboard interaction in some positions, and it must be done carefully if you want very low action from your instrument.
My fingerboard has a "flat spot" under the E string. What gives? You may have seen some bass fingerboards with a sharp rise or beveled edge that runs the entire length of the board, between the A and E string on some basses. It is called the "Romberg Bevel." It was invented by (and named for) Bernhard Heinrich Romberg (November 13, 1767 – August 13, 1841), a German composer and cellist. That shape is a throwback from when big fat E strings crawled the earth -- the bevel gives more clearance for that string to vibrate more clearly. With newer string technology, it's no longer a necessity and many luthiers and builders have phased it out. Some folks prefer it, some don't; it's probably just a matter of what you're used to, but no biggie IMHO.