What is the difference between Oil and Acrylic paints?
Do you want to learn to paint put don’t know where to start?
Get excited about all the paintings you are going to create but don’t know which types of paints to begin with?
To understand the pros and cons you need to ask yourself a few simple questions to determine which medium is best for you…
Please note: The comparison below is for standard acrylics and oil paints, not taking into account quick drying oils or ‘Open’ acrylics (slow drying)
1. Do you work quickly or slowly?
Acrylic Pros: You can paint on anything.
This is one of the key things that make acrylics a great medium to start with when beginning to learn to paint. To be able to set up quickly, start painting on anything is brilliant. Paper, card, canvas board, whatever you have to hand.
Acrylic Cons: They dry quick, I mean really quick.
You want to do some painting, so you book in a little me time. You’ve got a canvas ready, you’ve prepared your ground and now you’re ready to paint.
All is quiet and at peace with the world. You carefully squeeze out your paintings, being careful not to use too much, and then what happens?
The phone rings.
Wrong number.
In this short amount of time the first blob of paint you’d squeezed out will now be dry, solid, unable to shift. So you scrape it off, squeeze out some more, ready to go and…
A knock at the door.
You put down your brushes, come back 10 minutes later and every thing has dried! Not quite the tranquil painting experience you had imagined.
The solution?
- Squeeze out more paint
- Add a retarder to keep the acrylics wet for longer (no more than 15% or the paint goes funny)
- Use a stay wet palette to keep the paints moist. See my video on How to set up a stay wet palette.
Oil Pros: Longer working time.
Because oil paints stay wet for a lot longer than acrylics it gives you the flexibility to start a painting and then come back to it the next day and continue straight where you left off. The paint on the palette will still be wet and pliable, the colours on your canvas can still be blended together.
Oil Cons: Preparation is key
Due to the corrosive nature of the oil (in oil paints) you have to work on a prepared canvas or board. If you are going to prepare the surface of the canvas yourself the preparation time is longer. You could of course buy a pre-primed canvas and get going straight away.
2. Do you like subtle blends or hard lines?
Acrylic Pros: A Crisp edge
The crisp edges that can be achieved with acrylics can be hugely beneficial if you paint with a more graphic composition. You can mask out areas, work over them quickly, and easily cover a hard shape with thicker paint. You can achieve clean, bright colours very easily.
Michael Craig Martin
Acrylics Cons: Achieving a smooth blend
Blending with acrylics can be frustrating due to the rapidness of the drying time. Especially if you are working on a large scale it can be practically impossible to work the canvas as a whole to bring it all to the same finish together.
This is for a size of say 6ft x 4ft. If you are working smaller that this you can achieve some lovely blends.
You can achieve smooth blends with acrylics you just have to work quickly. You can add a medium to the paint to help keep the working time open for longer. Either use soft gel gloss, retarder (slows down drying time) or my preferred choice, glazing liquid gloss.
Pro tip: I use the glazing liquid gloss even if I don’t need a gloss finish. This is because the matting agent used in the matt glazing liquid is white when wet, it dries pretty clear but i have found it can sometimes leave the blacks looking milky)
Oil Pros: smooth blending
Oil paints are king of the ring when blending colours together. Because of the slow drying nature of oil paints they can can fantastic for creating subtle blends.
Working wet-into-wet is the sure fire way to get a smooth transition in your painting. This is especially true for portrait painting when the subtle shading of the face can need constant revisiting and tweaking. You can also add slower drying oils to your paints to create surfaces that can stay wet for weeks.
Oil Cons: Trying to create a crisp edge without it effecting the underlying colours with oils means you have to wait until the next day, or touch dry otherwise your brushstroke will pull and mix with the paint underneath it. It is very easy to achieve ‘muddy colours’ when first starting with oils due to everything staying wet and the colours mixing together on the canvas.
Solution: Experience teaches you to work cleanly.
3. Colour shift
Acrylic Pros: They are lightfast
With projected laboratory tests acrylics won’t fade in time, the colours will look the same now as they will in 200 years. The binder in oil paint – oil, goes yellow over time, this causes the subtle glow on old master paintings with acrylics they are colourfast, the binder – acrylic polymer doesn’t yellow over time.
Pro tip : The most likely cause of fading is using pigments that are not lightfast, this is true of oils and acrylics.
Acrylic Cons: They change colour when they dry.
The binder used in acrylics is usually white but dries clear (the recent binder in Winsor & Newton Artists’ Acrylics is clear, but I feel still has a slight color shift) This means it appears lighter on the canvas when you first put in on, and then dries darker as the white binder turns clear.
This becomes really apparent when painting portraits. You think you’ve cracked the precise colour, turn around and the colour has changed. With practice you can learn to judge to shift but it can be disconcerting when you begin to learn.
If you add more acrylic polymers to the paint, in the form of mediums (quick dry mediums, flow release medium) the colour shift will be even greater.
If you use student quality paints that have extra fillers added, which are often white, the colour shift will be more pronounced.
Oil Pros: No immediate colour shift.
Initially oils stay the same colour when painted on a canvas. However, once the colour dries it can appear to change if the oil from the paint ‘sinks in’ to the canvas.
This can lead some areas to be glossy (still have the oil in) and others to be matt (oil has been soaked into the underlayer) to produce a deader colour. To overcome this you have to “oil out’ the area of the painting you are working on. A paint surface can appear dull and is usually caused by too little oil in the paint film due to the absorption into the ground layer (or overuse of thinners such as turpentine)
Pro tip: In classical painting you build an oil painting up in layers and one of these layers is called the ‘dead colouring layer‘ It is painted using oil paint thinned with turpentine onto an absorbent gesso ground, this soaks up the oil, speeds the drying time and gives a local colour to the painting.
Leonardo Da Vinci, Adoration of the Magi, detail.
Oil Cons: Yellowing
Oil paints will have a slight yellow tinge to them due to the colour of the oil (think of olive oil) As oil dries over time through the process of oxidation additional yellowing takes place. This varies in degree depending on the binder used in the paint.
“Yellowing must therefore be considered as an unavoidable characteristic of drying oils and this must be kept in mind by users.”
Professors Mallegol, University Blaise Pascal in France.
4. Do you like working with thick paint or thin layers?
Acrylic Pros: Acrylics are flexible.
If you like the idea of using a palette knife and creating thick, impasto paintings, acrylics could be the choice for you. You can paint thickly, build it up and the paint will dry. If you try to achieve the same with oils the outer surface will dry to the touch but the inner paint will still be wet.
You can also work very thinly with transparent glazes or very thickly with a mountain of paint but the actual surface quality of the acrylic remains flexible, this means your painting won’t crack over time.Thin coats of acrylic paint can be used to give a watercolour look to a picture.
Pro tip: Acrylics can crack but usually only in extreme cold temperatures.
Oil Pros: Long drying times
If you have plenty of time set aside for your painting, oils can be fantastic. You can work with thick paint, wait a couple of days for that paint to dry then add thin glazes to create luminosity in your work.
Oil Cons: To work with thick paint you need to take into account the drying time of oils. Each particular pigment needs a different amount of oil mixed with it resulting in a different drying time, e.g: Earth colours such as Burnt umber is a rapid dryer whereas Ivory black takes much longer to dry.
The solution: Add a siccative to the paint. A siccative is a medium that helps to speed up the drying process in oil paints. Traditionally this was a cobalt drier, more recently, Liquin by Winsor & Newton is a synthetic medium that can accelerate the drying time of the oil paint by about 50%
5. Do you work in a small space?
Acrylic Pros: Acrylics can be a great alternative to oils if your working in a confined space are working with kids or in a unventilated area. You just need access to water. Acrylics have no smell, and are non toxic.
Oil cons: The smell of turpentine
If your start painting with oils in a confined space the fumes from the thinners can overwhelm you, turpentine and white spirit can be really strong. White spirit can also be a irritant to the skin and turpentine rags can spontaneously combust!
I work with odourless mineral spirits or ‘Zest It‘ (a thinner made from citrus ) that have a very minimal odour compared to turpentine.
Pro tip: The odourless mineral spirit does not cut through the oil as well as pure artist turpentine and if you are using Dammar varnish in your mixes can cause problems.