How to finish an acrylic painting – part II

Golden polymer varnish and self-levelling gel

In my last post about this I spoke about the procedure as a whole, with a few whys chucked in for good measure. Here I would like to talk about the nitty gritty how.

So I’ve finished painting a painting, I’m happy with it.

  • The first thing I do, as mentioned in Part I is to let it dry for at least a week, maybe two, or more, depending on how lazy or busy I am at the time. This allows all the volatiles to fully evaporate from the paint.
  • Leaving the painting like that can also introduce a painter’s nemesis into the equation – dust. Make sure you put your painting in a place where it will get the least amount of dust or paraphernalia dumped on it. The kitchen table or anywhere is in a child’s reach may not be a good idea. I have a studio drying area, but yeah, dust gets there. Also once you need that drying space for another wet painting and you end up putting the dry painting on the floor leaning against something, watch for floor grot getting on the bottom edge of the painting and make sure you leave it leaning for as short a time as possible or you may be introduced to another artist’s nemesis – gravity. Canvases left leaning at odd angles or without the correct support can buckle – then your beautiful painting will either have to be restretched or firmly framed before you can sell it.

    Dust in isolation coat
    Look closely – a white background I coated in isolation coat and forgot to dust first. This is sitting in my studio awaiting repair (it will not be for sale).
  • When I’m ready to start varnishing, I lay the painting flat on a plastic covered table (I use plastic polythene painting dropcloths, the blue sheet in the photo above – they are fantastic in that the acrylic paint can’t stick to them). Do not varnish with the painting on an easel, you risk drips and thicker varnish at the bottom of the painting. Wipe off any dust with a dry brush or soft rag. If the dust is particularly bad I will use a damp cloth to wipe it off, but then the painting must be left to dry.
  • Be aware of your environment. If you live in a climate of extremes, watch the temperature. In Adelaide we have extreme summers, but mild to cold winters – up to 40C/104F+ in summer down to rare below 10C/50F daytime temperatures in winter. The summers have the obvious problem of paint and mediums drying too quickly. I highly advise not varnishing in high heat, you risk damaging your painting. Running a brush over dry or wet varnish or medium is okay, but running a brush over half dry of either can create lumps, bumps or foggy finishes.  In cold extremes you must watch the setting temperature of the paint or medium you are working with. Both the Golden Self-levelling Gel and the Polymer Varnish with UVLS have a minimum setting temperature of 9C/49F. It has been cold here recently and I found that the gel was thicker in the colder temperature, so I added a dash of water to thin it slightly so it flowed properly. Humidity is also a factor to consider, but not one I have encountered much, as it is very dry here most of the time. Know your climate, know your materials’ capabilities.

Golden self-levelling gel

  • Apply the Self-levelling Gel with an acrylic brush. I like to use a crosshatch technique, but watch out if you get too enthusiastic because foam can form and if the bubbles do not escape, they will set cloudy. Try for a thin even coat. Be careful when coating paint irregularities on the surface, make sure you brush any accumulation of gel off ridges and lumps. Coat the entire painting including the four sides of the canvas.  I work like a typewriter – paint left to right then return to the left and start painting left to right again. My reason for doing this is because if I paint zig-zag (left to right then right to left underneath), by the time I get back to the left, it may have dried just that little bit too much and joining up the wet with the partially dry can be perilous. Watch when you are running the brush over the edges or corners that you not inadvertently create drips or ridges.
Adding the isolation coat
Adding the isolation coat – it goes on foggy white and dries clear.
Foaming in self-levelling gel
I really stuffed up on this one – the white froth is self-levelling gel.
  • Let the coat dry for at least a day, preferably two, then apply a second coat. Let dry a day or two further, but preferably a week (but this is often not practical time-wise, but leave it as long as you can).
  • When coating in varnish, I use a soft brush, Golden recommends a stiff brush. The varnish is much thinner than the gel and requires a little dilution 4 varnish : 1 water before application. If you are using a satin or matte varnish, make sure you use a palette knife to stir it gently to ensure the matting agent is evenly distributed in the liquid before mixing the required amount. Try to mix enough varnish for two coats. Nothing like racing varnish drying time halfway through while trying to mix up a new batch. Mix the varnish in a resealable container – I’m a fan or recycling polypropylene containers (in Australia, that is recycling code PP 5) for the same reason I use the plastic drop cloths – dried acrylic peels off and I can reuse the container. Dip and sauce containers are great for this.
  • For the varnish I use the same crosshatching technique that I use for the gel, however I find that my touch must be much lighter, and overworking a spot can create a massive amount of bubbles that I then need to gently brush out. Avoid bubbles as much as you can – these are the source of fogging. Again, watch paint ridges, edges and corners and make sure you leave no build up in these spots. Varnish, being so thin, is very prone to running – watch the edges of the painting and if the varnish runs over the side, brush it so it doesn’t leave drips.
  • Let the varnish dry for a day or two between coats, and then a few days more once the second coat has been applied and before hanging.

For a thorough run down on how to varnish with a particular varnish, make sure you read the documentation. For the Golden Polymer Varnish with UVLS there is an excellent set of directions and information on the Golden website. In Adelaide, Golden Paints have been traditionally hard to find, but now they are readily available at Art to Art, Duthy Street Art Supplies and Port Art Supplies. I have also bought them at Dick Blick in the US by mailorder when I need large amounts, even with the postage it has been cheaper.

Do you have any hints or tips to share? This is what I have worked out, I’m sure there is more on this topic I am yet to discover.

Best wishes,


2 responses to “How to finish an acrylic painting – part II”

  1. […] will get into the nitty gritty about how I actually apply the isolation coat and varnish in Part II of this post. I hope the above has been useful to some. Do you have any varnishing hints and tips to […]

  2. Thanks for the in-depth post on acrylic finishing! I knew the basics, but your explanations is one of the best ones, I’ve seen in a while! Keep up the great work and tutorials!