tk, vnc, and Couldn’t open RGB_DB ‘/usr/X11R6/lib/X11/rgb’

I am filled with a terrible hate. How is it that I spent 2 hours debugging this problem? When running a tk application from within tightvnc, I got this error message:

error initializing Tk: 'this isn't a Tk application unknown color name "Black"

I eventually noticed that I was also getthing this message in my tightvnc error logs:

Couldn't open RGB_DB '/usr/X11R6/lib/X11/rgb'

I suspected this had something to do with rgb.txt not being in the expected place. But here’s the final piece of the puzzle (from the man page of xorg.conf):

Note that an implicit .txt is added to this path if the server was compiled to use text rather than binary format RGB color databases.

So all it took to fix the problem was this:

sudo ln -s /etc/X11/rgb.txt /usr/X11R6/lib/X11/rgb.txt


  1. anonimous says:

    Had the same problem. Now solved. Thanks a lot!

  2. Denis Howe says:

    I’ve been struggling all evening to get a VNC server working on Ubuntu. This was the final clue I needed. Thanks.

  3. MR says:

    It seems I have the same problem, but I’m not root…
    Any idea what to do in the case you can’t create that symlink down there?

  4. Mike says:

    Yeah, sorry no

  5. frank says:

    this is what i did to get it to work under debian 5.0.10
    cd Xvnc
    make clean
    vi programs/Xserver/dix/Makefile
    change DEFAULTRGBDATABASE = /etc/X11/rgb
    change FONTDIR = /usr/share/fonts/X11

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