thanks Zhann for the suggestion - I do that and 90% of the time, it's fine - it's just that sometimes it just won't keep the new settings - on occasion i have found it to jump back several settings as i save it. i am beginning to wonder if it is something to do with how Bryce handles memory as it seems to be more likely to go nuts after i've created several materials either that or the materials lab is just holding its own minor rebellion :)