Mixing brands of acrylic paint
Image: © 2006 Marion Boddy-Evans.

The question whether it's okay to mix different brands of acrylic paints and mediums is one that comes up regularly. I asked Michael S. Townsend from the Technical Support team at Golden Artist Colors, Inc., about the issue. Golden are dedicated to producing quality artist's materials and not only do a huge amount of research but also provide detailed information sheets on their products on their website. This is what his response was:

Answer: This certainly is a fairly common question for us as well. Because our product line is vast, we have to build in a great deal of compatibility within our own products. This tends to translate well when artists desire to blend our product with other brands. While in general there tends not to be any problems doing this, there are things to watch out for when you do this.

Most acrylic paints have to be on the alkaline side of the pH range for stability. However, some manufacturers tend to leave paints on the low side and others on the high side. When these opposites meet, a pH shock occurs and the mixture can be lumpy like cottage cheese. It tends to be temporary and normally will smooth out if they are mixed for a while.

If the paint mixture begins to get very lumpy, mealy, stringy, or some other adjective that should not belong next to the word paint, there most likely really is an incompatibility and I would suggest not using that mixture.

-- Michael S. Townsend, Technical Support team, Golden Artist Colors, Inc.

In my own painting I regularly mix different brands. While I do have favorite brands, I do like to try new colors and unfamiliar brands (see How to Assess a New Paint). I've not encountered problems with paint interacting -- no cottage-cheese textures or adhesion problems -- but I have inadvertently used a slow-drying acrylic when I wanted something to dry rapidly (see Drying Times for Different Brands of Acrylic Paint). Annoying, but not disastrous.