If you find a blending mode and opacity for a particular texture that you like better than the default, you can save those settings as the new default by clicking the Save Settings button. Your saved opacity and blending mode settings will automatically be set for that particular texture the next time that texture is selected.
If you mess up a texture’s settings, and want get back to the original settings that we here at Totally Rad HQ prefer, hit the Restore Defaults button. Everything in the Dirty Pictures texture library comes with a backup of the original settings that can be restored by pressing that button. Think of it as an escape hatch.