Making reverse moulds for silver fingerprints

Hi,

I've been making silver fingerprint jewellery for quite some time but am still not happy with the quality of the reverse moulds. I have used both Siligum and the more expensive brand with the Chinese writing on but the reverse moulds are hit and miss often coming out with air bubbles. I line with badger balm and try to press down to eliminate air bubbles but they still appear.

Additionally there is sometimes loss of detail but I don't know whether this is inevitable?

Would be very grateful for any advice!

Many thanks!