Available in a 4 oz jar 

The Matisse Derivan Company manufactures the Heritage MultiMedia Acrylics in Rhodes, Australia. Not only is the Derivan Company dedicated to making quality, environmentally responsible products, but they are also advancing the science of paint making. They have two new mediums that are compatible with Heritage MultiMedia Acrylics.

Matisse Open Medium (from the Matisse Derivan website)

Optimal for painting outdoors or in particularly hot weather, MM31 Open Medium allows the paint to be blended on the painting surface for longer. Artists will be delighted with the way this medium makes their paint handle, so smooth and buttery. Be surprised by the glowing satin finish that this medium imparts to the paints.

Mixing Ratios

As little as 10% MM31 Open Medium to the paint, will lengthen the working time, allowing satisfying, smooth blends. Adding small amounts of the medium with increase the working time without drastically increasing the overall drying time. However, a larger amount of Open Medium will dramatically extend the working time on both your palette and surface. The maximum extension of working time is  with a 50% ratio of medium to paint. Beyond this point, you risk thinning the paint's binder and it may reduce waterfastness of the dried color. However larger proportions (more medium than paint) will give transparency and will aid effective layering.

As well as allowing more time to blend on the surface, paint mixed with MM31 Open Medium will stay fresh on the palette for several hours, depending both on the weather conditions and the quantity of MM31 Open Medium used. Easy to use, MM31 Open Medium will allow the reworking of areas of a painting in a way not previously possible.

The gel-like consistency of MM31 Open Medium allows it to remain in place on the palette, therefore it is suitable to be brush-mixed while painting, as well as to be pre-mixed on the palette.