The photos in the previous post are silver etched with nitric acid for 20-30 mins. These photos show some of the etching that I did in my home studio later today with ferric nitrate. In this case the etch time was 50 mins, and the etch is more delicate - in this case very fine text. Ferric nitrate takes longer and is a more delicate etch compared to the aggressive bite of nitric acid. It is also a less dangerous substance, though still hazardous and (obviously) corrosive (not great when you have two young boys in the vicinity).
It will be interesting to see how these look after I have oxidised (darkened) the text. I think they will work well and retain their detail, but especially in the case of 'love is all you need' I think this will need to have a brushed finish, as any dramatic polishing might just remove the text! I'll have another play tomorrow and will try leaving them in longer. There is a always a worry that the protective film will peel off, the longer you leave them, and then the whole etch gets ruined.