First make a back up copy before preceding.
locate the folder in this dir
Program Files\Pixologic\ZBrush3\ZData\ZPlugs\SplashData
you will see a text file called Startup.txt
the dir/ directory will be like this depending on what drive your have it installed
mine shows C:\Program Files\Pixologic\ZBrush3\ZData\ZPlugs\SplashData\Startup.txt
in the Startup.txt edit the top line by placing this
[IColorSet,148,148,148]
[ISet,Document:Back,148.58038]
[IColorSet,254,254,254]
when you start up zbrush 3 your background color will change.
so you want to chose your own color instead of one i posted?
first start zbrush and pic a color
then press Document>Back
now end the record and open up that text file in a note pad
look at the bottom of the text file and you will see some thing like this
[IColorSet,148,148,148]
[ISet,Document:Back,148.58038]
this will change your background color
BUT you will need a third code to set the color back to allmost white
so ill place this at the bottom
[IColorSet,254,254,254]
ok now you have the 2 codes from the text file and then add the third to the bottom
so it ill look like this.
[IColorSet,148,148,148]
[ISet,Document:Back,148.58038]
[IColorSet,254,254,254]
in the Startup.txt edit the top line by placing the code above.