Vetro black and mucky silver colours

[garishglobes]

I've been trying to use striking silver colours (Khaos, Terra, Terranova, Raku 104) over Vetro black - and the results are just disgusting! Yukky greys, sludgy browns...
Actually, the Raku 104 I tried with some silvered ivory over Vetro black and it devitrified (if that's the right term..) as well!!!
I thought Vetro black was fairly unreactive so I'm a bit surprised by this! Anyone else have the same thing? I wasn't really planning on a "more glass" purchase after recent sprees, but these are so foul I'm wondering whether I'm going to have to get some basic Effetre in!!

[Sherry Bellamy]

I no longer use vetrofond black, but that's because I was having problems with it getting a nasty haze. To me, it's never been as good with silver as the effetre....but some people love it.

[garishglobes]

Hmm... well, I'm still having problems. Looks like Effetre it is!