Mono printing is so typical of many forms of making backgrounds in that you generally get "one go" at it and if you try and repeat the exact same thing, it never works out. I'm thinking alcohol inks particularly here!!! You can use the same colours as previously, think you are doing the same movements or application but nope, it just doesn't look the same. So mono printing is named as it's a single print. I used a combination of acrylic paints (Jo Sonja work just fine) and some of the various metallic paints that are around, love the Plaid ones! I also used stencils to add interest and even the humble bubble-wrap makes circular marks in the paint layer before you lay down the card. I've used both smooth watercolour card as well as a heavier weight gloss card as they both work but give different looks to the backgrounds (which of course you can't see on the computer). I love background classes.
"Vampires"... (no stencil works just fine)
"Landscape Painting"... (a beautiful lattice type stencil was used on this one)
"Bee fierce"... (I used a hexagon shape stencil on this background)
"Little sparkle"... (this one has the bubble wrap on the background)
This gives you a better idea of how they turn out.