Main points of difference- Acrylic vs Oils


There was a time when artists and art buyers felt that there was a superiority in oils compared to acrylic. Throughout history, the lack of knowledge of the science of oils has been responsible for the breakdown and deterioration of paintings (sadly some very valuable ones) .Those cracks are a result of the tensions between 'fat and lean' layers of paint. (more on that in the oil painting sections). Once dried, good quality acrylic paint forms something akin to a sheet of plastic and as long as the substrate is suitable and the mediums and binders were of high quality, cracking and deterioration will not occur and a student does not need to worry about 'fat over lean' etc, hence modern high quality acrylics are more durable and safer for artists in many ways. (of course we have not seen them after hundreds of years, but scientists predict they will not crack)

The three main drawbacks of oil paints are :

* the care needed with layers being increasingly 'fat’, 

* the fumes if you use traditional solvents, (in the oil painting course you can learn how to use both traditional and water mixable oils without ever using harmful solvents, in painting or in clean-up)

* the drying time is very long with oils compared to acrylics. 

The main benefit of painting in oils

The principal benefit of oils is their ability to blend effortlessly, a great help to those wanting to achieve highly realistic modeling of smooth figures and objects, and they also have absolutely no tonal shift with drying. What you see wet is the same as when dry. Some say the colours are more vibrant, but a good quality artist’s acrylic is as vibrant as any oil paint.

The three main drawbacks of acrylic paints are :

The principal drawback of painting in acrylics is the same as it’s benefit (a twin-edged sword, so to speak): they dry so quickly that seamless blending is quite limited compared to oils. Most brands of acrylics have a retarder medium available, a glycerin type liquid which slows the drying somewhat, however, it can get tacky and tricky in warmer weather.There are also “open” acrylics from a few major brands, but watching students with these over the years, I have found it hard to convince them to use the appropriate drying/ binding mediums properly that are required to “cure” the layers, and I have also noticed that they get sold the wrong combinations by many art shop staff. I believe it is better to get a very fine atomiser with boiled/filtered water and “humidify" the working surface as you go along. If this does not give you the blending boost you need, block in with acrylics and use a single blending oil layer to finish.

Another drawback which bothers some painters is the slight darkening of acrylics as they dry. This is because the polymer emulsion in which the pigment is suspended, is white when wet, and transparent when dry. Once you know your pigments well enough, this is only a minor deal. Actually Winsor and Newton have developed a transparent emulsion , hence the paint has no tonal shift with drying. The W&N acrylics dry a little slower than many others as well . I actually find the faster drying ones best in a class room setting. If students use a stay-wet palette and make up decent quantities of colours for each project, they don’t notice the problem of the next mix drying slightly different to the first.

The main benefits of painting in acrylics:

Both liquid and heavy body acrylics dry very fast (compared to oils), so moving forward in an art work is a breeze, once you learn how to control your brushwork (a matter of practice). Glazing is quick and easy with either water or for larger areas a liqud medium , as long as you have good transparent pigments.  Multiple textural techniques can be overlaid in no time and textural ideas can be developed as they come, rather than lost while "watching paint dry “ over weeks, not minutes. For learning, they are excellent because students can be bold knowing how quickly and easy they can paint over little blunders.

As far as we know, acrylics are far more durable than oils, without the requirement of the scientifically proven  “fat over lean” necessity of layering oil paints.

I love returning to use oils and watercolours to demonstrate to a keen student, but in my own practice, acrylics (both liquid and heavy-bodied) are most definitely the most advantageous. I think each of us must find our own preferences as we go along and never be afraid to turn to another medium if the call arises.

Acrylics (left) vs oils

one vs other

© Port Art Gallery 2016