Changes made to the logback.xml do not require a restart to load; Artifactory will reload the configuration after a few moments, you should see this entry in the log:
2014-04-30 19:56:30,410 [logback-watchdog] [INFO ] (o.a.w.s.l.LogbackConfigListener$LogbackConfigWatchDog:138) - Reloaded logback config from: C:\Soft ware\Artifactory\artifactory-powerpack-3.2\bin\..\etc\logback.xml.
The debug messages will be logged in the artifactory.log