Our March gelli technique swap was to use masks. This technique is demonstrated with fabulous results on theGelli Arts blog here. They make it look so easy but I was right, it is getting trickier.
I don't think the odd assortment of paints I used were entirely suitable though - our swap hostess recommended translucent ones but mine were rather opaque so I ended up with horrid dark prints. Well that's my excuse anyway. And you can tell they were bad because they went in the bin and it is not often I throw things away without at least trying to redeem them with a little bit more of something.
I used the second "ghost" prints for my post card in the end. Because I printed an A4 sheet and then cut a postcard size out the pattern was rather large in proportion to the post card. I couldn't resist adding some background stamping in similar colours to balance the overall background.