I read on your web site that GOLDEN mediums allow blending paints by slowing the paint drying time. In the old days of acrylics I read retarding mediums adversely effect the permanence of acrylic polymer bond. Since I prefer permanence, I stayed away from retarders. What about your mediums that slow drying time? Will they keep the paint film permanent?
In terms of retarder, it is true if you add too much to your paint, you can make a poor paint film which is not as durable as without the retarder, however, it really depends on how much is added. The same is true for water, as these are both additives and not mediums; they do not add anything to the paint film. For thin applications, 30% is the maximum amount to add. For any applications heavier than a brush stroke, 15% is advised.

Finding the right balance with retarder, paint, water and mediums can be tricky. Without a lot of testing, the artist is left unsure, and often does not find the right balance of materials to get the proper open time. One of our newer mediums is called Acrylic Glazing Liquid. It's a combination of acrylic mediums, retarders, additives and water. The key difference is you can't really add too much to you paints because it's designed to form a film by itself. In the right application, you can get up to 45 minutes of working time with the acrylic paints. It’s very helpful for softer edges and blending, whether it's used as a translucent glaze mixture or just added minimally. There is a great Information Sheet at our web site about the AGL.