One of the most frequently asked questions in art materials retail is whether house paint can be used as a substitute for artists’ acrylics and gesso. The short answer is no, house paint does not generally perform as well as artists’ acrylics in terms of durability, lightfastness and appearance. Artists’ acrylics are similar to architectural paints, but there are some important differences. House paint is designed for different performance standards and applications than artists’ paints; this does not mean architectural coatings are inferior to artists’ paints, but they don’t always satisfy every requirement in the artist’s studio.
Artists’ pigments are tested for lightfastness ranging from average to excellent. (Colors of poor lightfastness are not used in professional-grade paints.) Not all colors are equally resistant to fading, but most used in professional quality artists’ paints are highly permanent, able to endure many years of normal light exposure without perceptible color change.
Pigments used in house paints are selected for mixing designer colors, usually with lots of white. Tints are mostly based on synthetic-organic (man-made) colors that need to last about 10 years without significant fading. That’s not to say that they may not last longer, but since walls are typically painted every few years, most consumers don’t expect or require better performance.
Vehicles and binders used in house paints vary from one manufacturer to another, but usually the term “latex” or “acrylic latex” is used to describe the polymer base. There’s no natural latex rubber in house paint- “latex” is a generic term for all sorts of water-borne polymer emulsion/dispersions.
Most manufacturers will not disclose exactly what polymers are used in their products, and not all synthetic emulsions are equally good for artistic painting. Many house paints are made using a more economical copolymer base that combines different resins, like styrenated acrylic (as opposed to pure acrylic). Styrene is more prone to yellowing than pure acrylic, so house paint color mixtures may not remain as originally mixed and a wall primer ground may not remain as brilliant or neutral as when it was freshly applied. Professional-grade acrylic paints, mediums and primers are made using top-quality 100% acrylic polymer base with stable, neutral color and excellent flexibility.
House paints sold outside the US are not always based on acrylic- many are made using a PVA base. Not all PVA is durable to archival standards; some types can yellow or become brittle from UV exposure. Also, since PVA is less flexible than acrylic, plasticizers are added to make the dry film more pliable. These compounds may not remain permanently in the paint, however, so a PVA house paint film may become more brittle as it ages.
In addition to pigment and vehicle, house paint contains a much higher volume of bulk materials like calcium carbonate (“marbledust”) compared to artists’ paints, and may include substances like talc not normally used in art supplies. These fillers are not as opaque or brilliant as white pigment so house paints don’t offer the same coverage and hiding power as artists’ paints. This is not usually an issue when covering a well-primed wall, but in complex layering on canvas the difference in performance is apparent. Also, fillers can render the dry paint film less flexible; heavy applications may crack.
Calcium carbonate is used in professional artists’ paints to provide body and workability, but bulk agents should never be used in a high enough proportion to compromise flexibility or affect color.