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Mastering your materials: technical advice from Amy Florence Moseley

Grinding paints at Studio Donatello, Florence

Amy Florence Moseley is the founder of Studio Donatello in Florence, where she offers courses and private tuition in academic painting methods. After moving to Florence at the age of 17 to study at Charles Cecil Studios, she taught at Charles Cecil for 5 years before striking out to set up her own atelier in 2013. Amy has a strong interest in the materials and methods of oil painting, and has accumulated an extensive technical knowledge over her years of working as a professional portrait artist.

We spoke to Amy to get her insights and advice on the technical aspects of oil painting, from stretching your canvas to framing the finished work. Here are Amy’s tips in her own words for how to master your materials.

Images: grinding paint at Studio Donatello (above); Amy Florence Moseley painting at Studio Donatello (below)

Amy Florence Moseley at Studio Donatello

Stretching and priming your canvas

As a painter you want to have as much control over your materials as possible, because then you know exactly how far you can push them and what you will get out of them. I find that when I stretch canvases I tend to stretch them quite tight, whereas the ones you buy pre-stretched are quite loose. I prefer painting on surface that is more taut.

The other advantage of stretching your own canvas is that you can choose exactly the type of canvas that you want – you’re not limited to what’s on offer in the pre-stretched range. I like to paint on quite a heavy weave, as the paintings that I like are often similarly on a heavy weave; I find if the canvas is too smooth and fine I am forced to be more sharp and rigid with my painting, whereas a heavier weave makes my painting a bit softer. Also I like canvases to have a bit of absorbency, because when they are too slippery they are, for me, not enjoyable to paint on…having said that, I do also like to work sometimes on a really difficult surface because it forces you to use paint in an unfamiliar way. I also like to work on panel because you don’t have the give that you have with canvas and you can get quite nice effects – for example I like to work on natural wood, sanded a few times with a few layers of shellac varnish, to give a nice neutral ground that also retains some of the wood grain, which can be nice to incorporate into a landscape or a sketch.

I would stay away from acrylic primers, a big reason being that they have started to find that paintings where acrylic primer has been used are starting to fall off the canvas after about 20 years – some of Andy Warhol’s work for example. Acrylics haven’t really been around long enough to demonstrate that they can stand the test of time. The other important point about primers is that the level of absorbency is crucial – you want one that will hold the paint but not completely suck the oil out of it. Instead, you want one that has a good balance between being not too absorbent but absorbent enough. Finding that balance, though, is a process of trial and error and being willing to experiment with different surfaces.

Preparing your paints

A lot of people are very intimidated by grinding their own paint, but once you learn how to do it, it’s the easiest thing in the world. I used to take a very long time to do it, but after a while it’s just instinctive. Grinding your own paint allows you to be very specific about the characteristics of the paint that you use. Because of the specific medium that I use, which is quite heavy, I need my paint to be strong and thick enough to stand up to the medium.

By comparison, a lot of tube paint has a lot of oil added to it because the manufacturers are trying to save money and because it needs to be able to come out of a tube. The type of lead white that I use – made to the consistency that I like it – you wouldn’t be able to put it in a tube. Mixing your own paints also allows you to have control over the thickness of the paint at different stages of your painting so that you can increase the thickness of the paint in the later layers.

I typically use a limited palette for portrait painting, so the pigments that I tend to grid are yellow ochre, lead white, and black. Vermillion I use straight from the tube as it’s a tinting colour. I start with a little mound of pigment and make a well in the middle – like you’re baking bread – into which I pour cold-pressed linseed oil. Ideally you want to get the cleanest cold pressed linseed oil that you can so that it’s not yellow. Aim for linseed oil as close to water/transparent in colour as you can find. I add less oil than I think I will need, mix it all together with the palette knife, and when it has all come together a bit I use the muller and grind it until I get the consistency that I am happy with. Sometimes I use too much oil and need to add more pigment, and sometimes I don’t have enough and I have to add more oil. In terms of consistency, I like to have slightly matte paint, especially with the black. I always think of a volcanic rock colour, almost grey, when grinding my black. The addition of the medium then provides the shine while still maintaining the body of the paint.

I grind all my paints to order – I’ll use it as soon as I’ve made it. Sometimes the lead white is a bit nicer the next day, so you can make it and leave it on your palette to tack-up overnight. Putting cling-film over the top of the paints on your palette will make them last longer, but the black and the ochre you never want to leave for more than 2 days because otherwise they start to go gummy. You can also preserve your paints by putting the paint in jars of water or by putting them in a fridge or freezer.

Grinding lead white paint at Studio Donatello Florence

Lead white

I use lead white, as opposed to zinc or titanium white, almost exclusively. Zinc, I have heard, can peel off the canvas the same way acrylic can, because that’s also a relatively new pigment so hasn’t had the test of time. Titanium is a very cold white, whereas lead white is a warmer, slightly yellower pigment. This warmth means that lead white has a much nicer tone for portrait painting, whereas titanium can make things quite chalky and cold.

On the other hand, titanium white can be quite useful when you want really bright intense light or colours like what you might get outdoors where you have an intensity of light that you don’t always get in the studio. Sometimes for landscape painting I will mix half lead and half titanium, and that gives a really nice buttery consistency – you’ve still got the body of a lead white, but with a slightly colder tone. When painting outside in the heat lead white can get quite short, and if you are doing a quick paint sketch you often want looser paint. Adding titanium white to the lead white is a nice alternative to just adding more turps or medium.

Switching to lead white was one of the biggest light-bulb moments I’ve had as a painter. Your white gets in almost all of your paint mixtures except for the darkest darks, and therefore it influences almost all of your painting. Lead white has this beautiful elasticity when you grind it, and when that gets mixed into your other paints you get a wonderful consistency of paint and a really beautiful paint surface.

When preparing lead white paint, you should be in a very, very well ventilated area, or if not you should use a fumehood. Wear a mask and also just be careful as you work, because you can see it lifting and it does float around the room…with the lead white I try to get it mixed with the linseed oil as quickly as possible to prevent it flying around the room.


The nice thing about oil painting is that there is no one single way to paint, everyone has their own way of doing it – my philosophy has always been that you first need to train your eye to see and then you invent your own language for painting. The medium that I use is the same medium that Rubens used: half varnish, half oil. The oil is sun-thickened linseed oil (which has been thickened in lead trays), and the varnish is two-thirds Canada balsam cut with turpentine (1:1) to one-third mastic cut with turpentine (1:1). What I prefer about this medium over just using linseed oil is that it gives you a lot more flexibility with the consistency of paint. You’re able to have very heavy impastos and very loose consistencies from the same medium by varying the amount of turps that you add.

Getting the ratio of paint, medium and turps just right for each stage of the painting is possibly one of the hardest things to learn when you’re starting to paint. It’s something that you get a feel for over time – you learn from making a lot of mistakes, such as really horrible, sticky, tacky paintings with areas that sink in (sinking in is when the layers below have more medium that the layers above, so the layer below will draw the oil out of the layer above and you end up with this matte finish). Ideally at the beginning you are using almost just turps, with a tiny bit of medium to give the paint a bit of gloss and richness; towards the end you are almost just using medium. The medium I use can get quite sticky, which is why you need good strong paint to stand up to it.

If you use only straight oil as your medium, you tend to get a very flat and uniform paint surface. With the introduction of the mastic in the medium that I use, you get a really nice fusion with the paint, so you can put paints down on your canvas and soften them together, and they will bind together on the canvas. By comparison, when using just oil and turning an edge, you have to mix every single half-tone along that edge and put them alongside each other. That can be fine when you are learning, but it’s not great if you want to have really soft edges. This varnish/oil medium also a glazing medium, which means you can let your surface dry and then make a very transparent consistency of paint and use that to glaze things slightly cooler, warmer or darker. Also the Canada balsam and mastic are varnishes, so you’re varnishing your painting as you go along, and there is no worry that the painting will look one way but then look different after varnishing.

Brushes and brush technique

With brushes it is good to start out with a general range of sizes and shapes. I tend to use the filbert (slightly round head) hog hair brushes – I use a lot more of the hog hair brushes than the sables, but I do also use sables. With the hog hair, you can put more paint down and you can make a softer mark. With sable brushes, they are a lot smoother, so you can make a sharper mark but you can use less paint with them. So when I begin a painting and I am working on the broad impression of the composition, I tend to use only hog-hair brushes. When you are honing in and trying to get more detail, sharper edges and highlights, then you need a sable to give you that kind of accuracy.

Softening edges is when you get a dry brush and a piece of paper towel in the other hand, and then you blend the edges of your painting and get rid of any sharp edges. It’s really important to do every day so that nothing dries sharp – especially when you’re unsure of what it is that you want to do with the painting. You want to allow yourself that flexibility. If you have a sharp edge, you are committing to that, but if you have a soft edge then you’re still within half a centimetre of an edge and have room to move.


I use the Zecchi finishing varnish that comes in an aerosol can. I don’t really like to put a brush over the surface of the painting with the varnish because you can end up with ridges, whereas with the spray varnish you get a nice mist across the whole surface that is quite uniform. I do two coats, holding the spray canister 40-50cm away and giving a very light mist. You must do it with the canvas lying flat, otherwise the varnish will drip down the canvas. Don’t overdo it – you don’t want your painting to be mirror-like, you just want to bring out the richness of the paint.

In terms of the time frame for varnishing, you really need to wait between 6-12 months before varnishing a painting. It seems like a lot, but I have paintings in my studio that are years old and you can still see that parts of the surface are in different stages of drying. For a while after finishing your painting you will have quite a patchy surface, and not until that settles down is it time to varnish it. If you don’t wait, then the varnish can fuse with the oil paint and if one day your painting is being restored then layers of glaze may be removed along with the varnish.

In the short term if you want to sell a painting before it is ready for proper varnishing, you can scumble the painting with a mix of turps and medium to bring out the colours, then varnish the painting at a later date. I always make a note of the date on which I sold a given painting, then will contact the owner to come and varnish the painting after sufficient time has elapsed for it to be ready for varnishing.


I have an ongoing argument with members of my family who say that you should be able to customise a painting like you can customise a car, and you should be able to choose a frame for a painting to suit your living room or wherever. My perspective, however, is that with a frame you are creating a window through the wall to your painting and you want a frame that stands up to its surroundings, wherever it is placed. Also if you invest in a piece of art and the frame doesn’t match the sofa, change the sofa, not the frame.

I used to use quite dark frames because they look contemporary and set a strong border between the painting and the outside world. However if you try to be too contemporary then your piece will look dated very quickly. It’s better to go for something timeless that will remain timeless. I am now leaning more towards entirely gold frames because of a lecture I heard about framing that was really inspiring. A painting is a piece of art and that should extend to the frame as well. Gold picks up the light in a really nice way and so that you get a soft, warm light that catches your eye and draws you into the painting. I have started gilding my own frames, which allows me to use different types of varnish to achieve a slightly cooler or slightly warmer effect, customised to the painting.

Never, ever frame your painting with a gap between the canvas and the frame. You want the frame slightly overlapping the canvas – the frame should be a natural extension of the whole composition. It’s therefore important to start considering the frame a few sessions into a painting. You could even get the frame made and put it on the painting before it is completed, so that in the last few sessions you can look at the painting in the frame and consider the completed piece. The frame should not be an afterthought.

If I do sell an unframed painting, then I will go with the buyer to help them pick a frame. When I don’t frame my own work, I take it to an artisanal framer who is an artist himself and has been framing for 30 years, who is able to give me guidance I trust. It’s important to get advice from someone with as much expertise in framing as has gone into the creation of the artwork itself.

Film maker Lejla Ustamujic recently made a short documentary film about Amy Florence Moseley and her atelier, Studio Donatello, which you can view below.

“He who works with his hands is a laborer.

He who works with his hands and his head is a craftsman.

He who works with his hands and his head and his heart is an artist.”

- Francis of Assisi -

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