Ever come across a painting tutorial and been stumped by new terms and phrases?
What is an Interference colour? Or a Tar Gel?
Inspired by one of the art school’s readers (cheers Carl!) I’ve compiled a guide to the most commonly used terms in acrylic painting.
Glossaries for oil painting, colour mixing, styles and movements are coming soon (sign up for free email updates so you don’t miss out)
Lets get going!..
Glossary acrylic painting terms
Artist – that’s you
Atelier – a small artist run studio school where students study the style and techniques of one artist. Atelier means ‘workshop’ in French, it is pronounced atel-yay. More commonly associated with oils, but we’re rebels!
Artist quality – the best quality (and highest priced) paints you can buy. They have a higher pigment load (amount of dry coloured pigment) compared to student quality paints, so a little can go a long way – see: 8 differences between artist quality & student grade paint.
Acrylic Gesso – an alternative to traditional Oil Gesso, using modern materials. It is a combination of chalk (Calcium Carbonate) and an acrylic polymer medium latex. The Calcium Carbonate increases the absorbency of the primer coat so watery washes of paint can ‘grab’ to the surface. Paint is then added to colour the mix, usually Titanium white.
Most ‘pre-stretched’ canvas’s bought from art supply shops have had a few layers of Acrylic Gesso applied in the factory – see: How to prime a canvas with Acrylic Gesso.
Binder – this is the substance that ‘binds’ a dry pigment together. For oil paints, Linseed Oil is the binder, for acrylic paints, Acrylic Polymer is the binder.
Blending – this describes a gradual transition between two colours, it is usually created when both paint colours are wet. As soon as one paint dries, creating a smooth transition can be impossible! This is often the biggest issue with acrylics due to the quick drying time.
Big look – observing the subject or painting as a whole. This allows you to view the relationship of the whole image working together and is often achieved by stepping back from the piece to get an overview – in contrast to working each small section at a time.
Blocking in – when you are first establishing the basics of a painting, you ‘block in’ the general colours or tones – the paint is often watery at this stage so you can easily paint on top of it. 90% of the blocking in will be painted over so don’t be too precious, just get the paint on the canvas so your eyes can start judging colours and adjust to the scene.
Canvas – Canvas is broadly split into two main areas, Cotton and Linen.
The most common used is Cotton duck canvas and is suitable for oils or acrylics. It is a reasonable price to buy and is available in large sections from the roll.
So why doesn’t everyone use cotton all the time?
The cotton canvas absorbs water, which has its advantages and disadvantages. The pros are the ability to paint with watery washes, or to soak the canvas surface and apply staining effects. The cons are because it absorbs moisture, it can stretch and shrink depending on humidity.
This is why on the back of stretcher bars (the wooden frames than the canvas is stretched upon) you’ll find expandable corner joints and wooden keys. These are used to adjust the tightness of the canvas surface if it begins to sag due to a change in atmosphere or humidity.
Linen is more resilient to changes in humidity and the fibres used in the manufacturing process are also longer lasting than cotton. This is why it is often a preferred surface for portrait painters due to the longevity of the material. It is more expensive than cotton.
So when you buy a ‘canvas’ from the art store, it will usually be a pre-primed, cotton duck canvas. This means the surface has had an Acrylic Gesso applied in the factory and is ready to paint straight onto.
Cotton duck – is a name for the type of textile used, the ‘duck’ comes from Dutch doek, which means cloth.
Canvas weight – this refers to how thick the canvas is, usually labelled in ounces, 8oz, 10oz, 12oz.
The choice of the weight of the canvas depends on the size of the painting and each artists personal preference. When a painting gets any larger than 6ft a 12oz weight is best – why? Because when stretching the canvas you need to apply strong pressure to the cloth to get a tight drum like finish and the danger is with a lighter weight canvas it can rip – see: How to choose a bespoke canvas.
Canvas tooth – the ‘tooth’ of the canvas describes the coarseness of the weave on the canvas surface. It is this jagged surface that helps to pull the paint from the brush onto the painting. Canvas is available in a variety of textures from extra fine (good for fine detail portrait painting) to coarse (good for textural, gestural painting) a medium texture is a good all rounder to start with.
Curing – this is when the acrylic is drying, but not fully dry. OPEN acrylics have a longer curing period than standard acrylics.
Coloured ground – a solid, opaque colour applied to the canvas (or painting surface) prior to commencing painting. It helps you to establish a tonal range to your paintings by allowing you to judge the lightest light and darkest dark as opposed to working with the glare of a white canvas. see: How to apply a coloured ground (video)
Consistency - the thickness or thinness of paint, basically how the paint ‘feels’ on the brush or canvas.
Cool – There are 2 things to consider in painting when using the word cool.
- The position of the colour on the colour wheel. For example, red is warm on the colour wheel, blue is cool.
- The coolness of the colour in relationship to another colour. For example, Alizarin crimson is described as a cool red in comparison to Cadmium red – but Alizarin crimson is warm in comparison to Ultramarine blue, which is cooler – but not as cool as you if you’ve understood this!
Direct painting – usually associated with oil painting, this describes a painting technique that uses solid, opaque blocks of colour. Rather than optically changing the painting by applying thin layers of paint like scumbles and glazes.
Dry Brush – an effect when you have very little moisture on your brush, to apply the paint you need more of a scrubbing motion and the result is called a scumble.
Flat colour – paint applied in a solid, flat colour, like the paint on your wall at home.
Flow medium – an liquid medium (Acrylic Flow Release) you can add to acrylic paint to increase the flow consistency whilst maintaining a solid paint film, this results in a more liquid paint with colour particles that ‘hold together. The most noticeable benefit is for staining effects.
It allows the paint to soak into a canvas really easily, rather than using alot of water to dilute the paint, which can sometimes result in the paint ‘pooling’ on the surface. The flow medium breaks the surface tension.
Glaze – a thin layer of paint used to optically affect the colour underneath. The underlying colour is already dry when the glaze is applied to add depth of colour and help fuse hard edges. Traditionally glazes were used on top of a black and white underpainting called a Grisaille, if you imagine glazes like a stained glass window, so the clearer the window, the cleaner the glaze.
The best paints to use for glazes are pigments that have a translucent quality. Modern man-made pigments can give you the cleanest glaze colour as the paint properties are already translucent. These are often pigments with names that are hard to pronounce! Such as Quinacridone Red or Anthraquinone Blue.
Ground - this is another name for the surface you are painting onto, if you just apply a white primer to your canvas, it can be described as a white ground.
Gel – a semi-solid material that you can mix in with your acrylics to drastically change the texture, consistency and can make your paint go a lot further. They vary from hard pastes to Tar gels that have the consistency of…. well, tar. See : How to use acrylic gels & mediums to see a demo.
Grisaille – using shades of grey in an under-painting to establish the tonal values of a painting. Traditionally used in portrait painting before applying coloured glazes to work the painting up to a full colour portrait.
Glazing Liquid – a medium that you can mix in with your acrylic paints to extend the working time and blending qualities of the paint. It is very handy for glazing if you are working at an easel because you can work in thin layers without the paint dripping down the canvas – this would happen if you only used water to dilute the acrylics. see : How to use acrylic gels & mediums to see a demo.
Highlight – this is the lightest ares of a painting.
Pro tip: It is best to apply the highlight towards the end of your painting once you have modelled the form underneath, have a look at the final parts of the cherry painting to see how this works.
Interference paint - when viewed from different angles the paint appears differently. Painted over a dark colour you can see one colour, paint the same colour over a light background and you see the complimentary colour. Add a very small amount of black to Interference colors to produce deeper, richer, opalescent effects.
Impasto – A thick application of paint, with textured marks or brush marks still visible.
Impasto suits Acrylics very well due to the quick drying nature of the paint and the texture gels you can add in with your mix. Impasto can be applied with a palette knife but usually refers to a brush application. Think Lucien Freud or Van Gogh application.
When dry, impasto provides texture and the paint sits proud of the canvas. It can be handy to convey a sense of form and to create a three dimensional sculptural feel.
In classical portrait painting the darks where kept thin and translucent and the lights thick and impasto.
Notice how, in Freud’s painting below, the highlight on the forehead is the thickest impasto part of the painting, especially in comparison to the thin background.
Lucien Freud, Self reflection (self portrait) 1985, detail, Oil on Canvas
Limited palette – When you deliberately restrict the number of colours that you are using in a painting. Instead of using 20 colours a limited palette would be 5. Notable realist painters, such as Singer Sargent, have used a limited palette extensively throughout their entire painting career.
Anders Zorn is noted to have only used 4 colours for 90% of his paintings. Titanium white, Ivory Black, Yellow Ochre & Vermillion. (so actually 2 colours + white & black)
This can be extremely useful when you are first starting to learn about the different qualities of pigments and the working characteristic of each paint. see: Jug still life demo using only 2 colours (40min video)
Load (pigment) - this refers to how strong the pigment is. Artist quality paints have a stronger colour and can be describes as having a ‘high pigment load‘. It describes the amount of pigment in the paint, compared to the amount of binder or other additives in the paint. Each paint has its own maximum pigment load as some pigment need more binder added to them just to be able to mix the raw material into a usable paint consistency.
Load (brush) - how much paint you have on your brush.
Masstone – the appearance of a paint colour when squeezed or applied in a thick blob of paint without dilution.
Medium – is anything you mix in with the paint to change its consistency, for example, water is a medium, Glazing Liquid is a medium. In Oil painting mediums often have a constantly changing recipe, depending on what layer of the painting you are on.
Open Time – length of time the paint remains wet enough for the brush to move through the paint.
Opaque – a pigment that doesn’t allow light through, as opposed to “Transparent” which is the opposite, and does let light through. Every paint pigment varies in it’s opacity due to it’s ingredients. On artist quality acrylic paint tubes, there is an indication by an actual painted swatch that will show you how opaque the pigment is – see The differences between Artist Quality and Student Grade paints for an example.
Palette – the surface that you mix colours onto, this can vary from wooden palettes, to glass, to tear-off paper palette. Acrylics, due to their fast drying nature, benefit from a stay-wet palette.
Palette (stay-wet) – A palette specifically developed for acrylic painting to counteract the quick drying time of acrylic paints. The stay-wet palette consists of two layers :
- An absorbent paper layer that is soaked with water – this acts as a water reservoir.
- A sheet of grease-proof paper – this acts as a membrane to stop all the water going into the paint immediately.
You lay your acrylic paints out on top of the grease-proof sheet and as the acrylics dry (they dry by evaporation) the water in the paint is replaced by the water that is held in the absorbent paper layer.
They can be great to extend the working time of your paints, just be careful if you use student quality paints as overnight the water can dilute the paint so much you’ll find your very own Jackson Pollock waiting for you in the morning!
Palette Knife – A flexible, metal blade used to mix your colours. Handy to stop the quick deterioration of your brushes (Free acrylic painting tutorial using a palette knife.)
Pigment – this describes the raw material that all paints are made from. Natural or synthetic materials are finely ground and mixed with a liquid binder into a paste to make paint. The binder can sometimes be called a ‘vehicle’ so for oil paint, the liquid vehicle is oil. The differences in properties of the paint, opacity, durability, light-fastness etc, all depends on the raw ingredients used.
Permanence – How permanent the paint will be overtime, for example, Permanent Alizarin crimson is more resilient to changes in atmosphere, exposure to light etc, than standard Alizarin crimson.
Retarder – a medium you can add to your acrylics to extend the drying time slightly. It slows down the chemical reaction but you can only add about 15% retarder to your paint mixture or the results are a weird tacky paint.
Rheology – this describes the flow properties of a paint or gel, it is often described as either “a long rheology” (like treacle) or “a short rheology” (like peanut butter).
Stretcher Bar - the wooden frames than raw canvas is stretched around.
Support - this describes the surface that you paint onto. It can be canvas, paper, board, all can be described as a ‘support’.
Scumble – A thin application of paint, similar to a glaze, but using semi-opaque and opaque pigments to alter the effect of the underlying paint. Usually applied with quite a dry brush effect.
Tinting Strength – this is a measure of much or how little paint you need to alter white. So for example, Terra verte has a low tinting strength so you need a lot of paint to alter your mix, whereas, Phthalo blue has a high tinting strength and you need only a tiny amount otherwise you overpower the other colours.
Undertone – this is how the paint appears when a very thin coat of paint is used. It’s easiest to see over a white background and is very useful for determining a colour bias, which is usually hard to distinguish when just looking at the masstone.
Vehicle – the liquid part of the paint, in which the dry pigment is dispersed.
Wash - a thin watery consistency of paint diluted just with water. It is most commonly used in the first blocking in stages of the painting, to gain an overall sense of the colour scheme.
Xylophone – just checking if you’re still reading!
Are there any acrylic painting terms you’re still unsure of?
Add them to the comments below and I’ll include them in the list.
Next week I’ll be posting a glossary of Oil painting terms.