This technique is one I read about in a book about alcohol inks & yupo. It's using a different surface for the alcohol inks to work on - chalkboard contact paper. Like the technique where we worked on the corrugated card that had been painted black, you need to apply a white alcohol ink before applying the colours of alcohol ink as the white allows the colours to show up. A similar technique I've used before is applying gesso over foil tape before applying alcohol inks, particularly the lighter colours of inks as the white base makes the colours pop much brighter than on just the plain foil. The 5 samples down the bottom are the atc sized pieces without any adornment on them so you can see how the colours actually are. Sometimes it can be quite difficult working on atc sized pieces of work for some techniques, but you just have to learn to scale everything back, in this case, the amount of product you use.... less is best!
Planet B sample.
This is one I haven't turned into an atc yet... love the colours though!