I am relatively new to acrylics and am currently 'experimenting' with acrylic pours to produce abstract pieces. On YouTube I watched a video by a German artist, Brigitte Koenig where she had a substrate submerged in a liquid (water?) and poured the acrylic directly into the water above the 'canvas'. When she removed the substrate from the liquid the acrylic adhered to the substrate and through tilting of the canvas she produced some wonderful effects.
I sent her an e-mail requesting a bit of information so that I could try the same technique. I wondered what her 'canvas' was and how it may have been pre-treated before subversion in the liquid. I also requested info on the nature of the liquid and also if her paints had been mixed with anything before being poured.
Unfortunately the artist didn't respond to my e-mail and so I'm hoping that someone might know the answers to my questions. If anyone has experience with this type of pour I would be most interested in getting some details.
Here is the link to her video: http://www.youtube.com/watch?v=ryJzgeWrRu8
She seemed to respond to inquiries on YouTube, although vaguely. After seeing a few of her videos a few things clicked for me as to why she did things, and it became a little funny to me in considering the wonderings of most people new to the art.
You can use any canvas board, the cheapies that come pre-gesso'd of several in a pack, that are preferably flat and medium sized, like 8x10 to 16x20 would probably be good. The larger you go, the more problems you get. Use of a leveling table is definitely a good idea to control the pour, as neat designs can slowly inch off the canvas in drying, the more you use a fluid medium with the paint. There is no "pre-treatment" needed as now days manufacturers prime and triple prime canvases to be ready to paint for you.
It looks like no medium was used in her paints really, because of how it does not flow well, except when water touches it, thus the lumpy parts that stuck to the canvas. The paint had to have been a thick enough paint to stick to the canvas while underwater, and she used water to get it to flow. But from her other videos it shows she used a small amount of fluid medium that is again diluted by water. What is the funny part is that she goes through all these experiments to add yet more binder (the salt looking substance in another of her videos) to get the diluted paint to stick!
All these concoctions can be avoided by simply using a paint that's made to be liquid to begin with so that there's no watering down of the binder, yet that will do the flow part. If you have normal thicker paints, you can still dilute the paint without water or at least too much of it, by using various fluid mediums out there. In her black and white video, you can see the dripping paint is not just drippy, but stringy in laying down. That is String Gel or Tar Gel (called different names by different manufacturers, but are essentially the same thing).
She probably diluted that too, as she is able to control the stringyness better. Like when you lift the pouring instrument up to stop, full strength stuff just keeps going like honey for a bit.. But she was able to stop it at will better, so that may tend to work in her favor, but a fluid medium could still be used with the Stringy medium instead of water. You add too much water and the glue goes too. For some reason, most people have the incredible need to thin their paints with water when trying this type of art, not thinking about the properties at play or knowing about them, that causes this stick problem when the binder is also diluted.
Some fluid paints to use are Golden's Fluid Acrylics, Acrylic Inks (I love the pearl colors and brightness of FW Pearlescent Acrylic Inks), and it is not really ink like pen and ink stuff with a quill, but is called that as an adjective because it is "like" ink, very runny, yet intense color & enough "stick" in it to do what you want. Liquitex Pouring Medium also dilutes the paint, to make it flow more, but with "adding" binder, not taking it away.
What effect are you trying to achieve?