black light

Discussion in 'Setup & Repair [DB]' started by billybass, Apr 6, 2004.

  1. billybass


    Oct 14, 2003
    New Orleans
    I just got a black light and would like to know other's experiences with them. I can easily see where new varnish has been added and where a bow was repaired. Is it possible to see if an instrument has been refinished?
  2. tplyons


    Apr 6, 2003
    Madison, NJ
    As far as I know, unless the previous finish was organic, it won't show, and if it's been well sanded, it won't either. Perhaps, it will work, definately a great theory. Is this a standard method of checking stuff like this? I've never heard about it or even thought of it.

    What do you see from the bow repair? Glue that squeezed out?
  3. basswraith


    Mar 10, 2003
    I used a black light to check out a bass once but it involved me taking it to a discotech. :bassist: I really dont remeber much about that night execpt the name Dita and a bad head ache.
  4. It would also be nice to know what happened to the bass..

  5. I've posted this before but can't find it now...

    Years ago I had a violin player/ repairman friend that studied varnishes in detail. He once showed me an old violin that bore the sort of wear, repair and dings one would expect on an instrument 100+ years old. It appeared more or less homogenous in colour under natural light. However, under black light, different areas of the instrument appeared light/ dark grey, black, salmon pink, even lime green in colour. It had obviously had the varnish touched in or polished over many times by many different luthiers with many different materials.

    Different compounds flouresce differently under black light.
  6. Except for a few high end violin experts who use it to help identify classic Cremona instruments, black light is of little use to the everyday luthier. The only practical use that I know of was shown to me by my friend Jeff Bollbach. Jeff sent me a bar of chalk that is black light Fluorescent. Great stuff for fitting bass bars and patches. It's barely noticable under normal light, but it really stands out under black light.