Transparency In Zbrush

Wanted to figure out how transparency in Zbrush worked so I thought I would add some bubbles to the scene.  Doesn't make a whole lot of sense to the narrative but got me looking at more tools and settings within the package.  The mask is just painted over so not rendered out but the bubbles use the transparent settings.  Not really a huge amount of control.  I think I keep at it a bit longer and then look to render it out in Maya to compare the results.