The plus point for me was the "noise" you get on the print - if you look at the leaf above you'll see that it's got traces of darker paint from the top layer of print, overlying the orangey paint I printed first. If I had used paper as a resist, I would have got a clean and clear print of a leaf with that underlying colour coming through completely - no noise. I like this!
It might be easier to explain if I post photos of the process.
The equipment: Gelli plate of a size that suits your paper, brayer, paint (I've used Open Acrylics), stencils, Vaseline, sketchbooks, baby wipes, scrap paper to roll your brayer on to get rid of excess paint.
Put a few spots of your chosen colours onto the gelli plate and use the brayer to roller the colour over the surface. Blend the colour as much as you wish. If you want to keep the colours more separate, then roller the brayer on your scrap paper to clean it.
Print the paint onto paper, labels, or your sketchbook.
Leave to dry.
Choose a stencil that you like - it can be anything, and be quite detailed.
Use your finger to gently rub the vaseline into the shapes on the stencil. Take care that the stencil doesn't move and you get a good covering. The vaseline shouldn't be thick.
Use a paper towel to gently wipe the excess Vaseline from the stencil.
Vaseline doesn't dry so you can start the next bit straight away! Roller more colour onto your gelli plate. I've gone darker with my colours so that it makes a good contrast.
Print the plate on top of your stenciled paper, and leave the paint to dry. This is important or the next step won't work properly.
When the paint is dry, use a baby wipe to gently rub the print and remove the excess paint and Vaseline. This bit is great fun as the print comes to life as the colours shine through.