Acrylic Gesso

A primer which dries with a coarser texture (or ‘tooth’) than regular acrylic primer. Acrylic gesso can be sanded down if desired. It is made from a mixture of chalk and pigment (usually titanium white), bound in a 100% acrylic emulsion binder. It can be used as a ground for both acrylic and oil painting.

Acrylic Ink

High-fluidity acrylic colour, made from pigment suspended in an acrylic based vehicle. It is usually sold in glass bottles, often with a pipette. Acrylic ink can be used in stamping, pen and wash, airbrush and drawing and painting. It is not re-wettable and is permanent and non-clogging.

Acrylic Painting Block

A stack of paper that has been specially prepared for acrylic painting (usually sprayed with acrylic primer), and glue bound on all 4 sides. A gap in the glue will be found on the corner or part of a side of the block, so that when the painting is finished and dry the top sheet can be separated from the block by running a clean palette knife around the underside of the sheet. A block is a lightweight support for acrylic painting that will not buckle during the painting process as the glue binding will keep the sheets taut and flat.

Alla Prima

A painting approach that involves completing a painting in one session. Usually refers to oil painting, the alternative is to complete an oil painting in layers waiting for each to be touch-dry before applying the next, so involves the fat-over-lean principle. Alla prima, meaning all at once, does not require observance of the fat-over-lean principle, as it is essentially one layer.


ASTM is the International Standard for testing and material qualities. On the labels of oil paints the ASTM rating will refer to the permanence of colours.


In acrylic painting, the binder is an acrylic polymer which pigment particles are suspended in to make paint. The binder is also known as the vehicle or emulsion.


Patches of cloudiness that can appear on the surface of varnished paintings if they have been kept in damp conditions. It occurs when moisture is trapped underneath the surface of the varnish or when the painting that has been varnished has not fully dried.


A woven material used for centuries for painting. Usually made of cotton or linen. Can be stretched over strong wooden stretcher bars, glued onto a board or panel or used unstretched. Although acrylic can be painted on raw canvas, most artists prime the cloth with a ground that allows control over the absorbency, texture and colour of the surface.

Canvas Board

Canvas glued on to a hard board (thin MDF or compressed board). A rigid surface for oil and acrylic painting. Canvas board usually has shear edges (i.e. the canvas does not wrap around to the back, unlike a canvas panel).

Canvas Pad

A pad of unstretched, primed canvas sheets glued at one side ready for oil painting. Also available in blocks glued on four sides.

Canvas Paper

Pads or sheets of paper that are textured and coated to have the appearance and feel similar to primed canvas. Used instead of canvas for economy and convenience.

Canvas Panel

A piece of board or wooden panel on to which a piece of primed canvas has been glued to the front and wrapped around to the back.

Canvas Pliers

A tool which helps to stretch canvas tightly around a frame in order to make a satisfactory surface on which to paint. Canvas is usually fixed to the frame using staples on the reverse of the frame, or tacks on the side of the frame.

Canvas Sheets

Sheets of rectangular or square pieces of primed canvas that can be glued to a board to make a panel, or painted on as they are.

Colour Shaper

A tool with a silicon or rubber tip and a wooden handle similar to a paint brush. Colour shapers can be used to draw into wet paint and create lines and textures, and are useful for closely scraping away small areas of paint.

Colour Strength /Saturation

Another term used to define colour strength is saturation. Colour strength can refer to the ratio of pigment to binder as well as the natural characteristics of the pigment, and is descriptive of how vibrant / brilliant / clean the colour appears.

Complementary Colours

They can be found directly opposite one another on a colour wheel. Because they are diametrically opposed they cause the appearance of one another to intensify when painted unmixed side by side. When mixed together they are capable of producing neutral greys.


The arrangement of shapes, colours and lines across your picture surface, sometimes referred to as a design.

Cotton Duck

A heavy plain woven fabric that is a popular material for artist canvas as it is relatively low cost in comparison to linen. Cotton duck is most commonly available in 10oz or 12oz weights.

Crackle Paste

When applied to a rigid support with a thickness of at least 3-4 mm, crackle paste will form cracks as it dries, which gives work an aged appearance or can be used for special effects showing through colours from underneath. It can be applied on its own or mixed with colour. The thicker the application the deeper the cracks. When dry, oil or acrylic paint can also be applied over the top of the paste.


The second stage of drying of acrylic paint. Acrylic paints dry when all the water found in the paint has evaporated, leaving the dried paint (pigment mixed into acrylic polymer). As the moisture leaves the paint film, the remaining tiny polymer spheres move closer together, causing the paint film to contract slightly. The pressure that is created by these spheres pushing against one another causes a capillary force which pushes the last of the moisture out of the paint film, until the polymer sphere start to deform and make bonds between one another. This results in the paint coalescing and forming a continuous paint film. Curing times will vary across brands so it is worth checking the manufacturer’s information if this is of particular concern.

Dry Brush Technique

The application of paint with very little water content in it using a dry brush. Applying paint in this way is also known as scumbling. The results can have a powdery appearance.


Wooden or aluminium support which holds your support in place as you paint on it. H or A Frame easels are designed for indoor painting, are sturdier and can hold larger supports. They are usually less compact and more difficult to move around. Radial easels are also for indoor painting but tend to hold a smaller size of support. They are more compact and easier to stack. For outdoor painting tripod field easels are available in wood and metal. These are lightweight, compact and easy to carry.


An emulsion is any mixture that doesn’t separate. In art this can be a cold wax medium or an acrylic polymer (acrylic paint).


The metal collar into which the hairs of a brush are bound. This can be crimped once, twice or three times to the brush handle.


In brush making terminology, the flag refers to the natural split found at the end of hog hairs. This improves the liquid holding capacity of the brush.

Flat Colour

A uniform application of paint, i.e. without any texture or undulation in tone.

Flow Release / Flow Medium

Reduces visible brushmarks and increases the fluidity of acrylic paint. The go-to medium if you want to create stains and washes on a porous or non-porous surface. Flow release breaks the surface tension of water, so allows fluid acrylic to spread rather than bead up. Many brands are very concentrated and you just need a drop, so they recommend making a bottle of water with diluted flow release to use. Some brands, like Jackson’s are already diluted so you use a full amount – so be sure to read the instructions on the label.

Fluorescent Colours

Bright glowing colours that absorb invisible ultraviolet light and reflect more light than they receive. By their nature the pigments are fugitive, both the fluorescent effect and colour will fade over time and should not be used for work intended to be permanent.

Fluid Acrylic

Fluid acrylic is made of pigment suspended in a polymer emulsion with a more fluid consistency than heavy body acrylic. It is not diluted with water and colours will be as stable and luminous as the equivalent in a heavy body range. Fluid acrylic is easily thinned for spraying as well as suitable for brushing and staining and can be modified with acrylic mediums.

Fugitive Colour

Fugitive colour refers to pigment that may fade or discolour when exposed to environmental conditions such as sunlight, heat or water. Fugitive colours will be indicated with a low lightfastness or permanence rating.

Gel (acrylic)

Acrylic gels are available in a range of consistencies and sheen. They are effectively acrylic paint without the pigment and can be used to increase transparency, extend colour and increase viscosity of paint. They can also be applied on their own to create transparent impasto effects on your surface. Gels tend to retard the drying time of paint and can also be used as a water, chemical and UV resistant adhesive in collage.

Gelli Plates

A printmaking matrix for a monoprinting technique that is especially effective when used with Open Acrylics.


Pronounced with a soft g like gypsy or George. From the Italian for gypsum, a major component. This thick white liquid is primarily used as a ground for painting but can also be used to build up areas for carving on frames and is used underneath gilding. It can be coloured. Gesso for gilding is often coloured red. You can buy ready-made black “acrylic gesso”.

Gesso is made with calcium carbonate (also called whiting, chalk and gypsum) in a binder. It is painted on the canvas, paper or wood panel surface to create a ground on which to paint. Sometimes white pigment (usually titanium, sometimes zinc) is added to make the gesso very white.

Genuine gesso (also called true gesso) uses animal skin glue (hide glue or rabbit skin glue also called “size”) as the binder and the artist often makes the gesso him/herself, using a double boiler to melt the glue powder and adding the whiting. Rabbit skin glue is now also available ready made and just needs to be warmed.
One recipe for traditional gesso: 3 parts size, 1 part chalk (whiting), 1 part pigment powder. It is a rather lengthy, messy, smelly process of soaking, heating in a double boiler and mixing.

“Acrylic gesso” is more correctly called “acrylic primer” and should not really be called gesso. It uses an acrylic polymer as the binder for the chalky powder. It is made up of upwards of 14 ingredients. You can also buy ready-made black acrylic primer.

Genuine gesso is less flexible than the “acrylic gesso” and is usually painted on a non-flexible surface such as a wood panel rather than on stretched canvas, so that it will not crack. For paints that need an especially porous surface, like egg tempera, genuine gesso is usually preferred to the acrylic gesso/primer.

The acrylic primer varies a lot in quality and poor quality products can provide a less absorbent ground than is often preferred. Good quality acrylic primer is a very good product for oil painting and acrylic painting. It does both steps of the surface preparation in one- it both sizes (seals) the surface and gives a ground for painting. It can also vary in absorbency, with some products called “acrylic gesso” rather than “acrylic primer” being more absorbent and chalky and particularly suited to applications which require an absorbent surface.

Acrylic primer differs in thickness, opacity and grittiness of surface texture, depending on the manufacturer. It is usually too thick to use straight out of the bucket and should be diluted with water until it is the consistency of heavy cream. Most primers have instructions that advise you apply three thin coats rather than one thick coat. A very thick coat may crack as it dries. The first coat is often scrubbed into the weave of the raw canvas in circular motions to be sure that it is well sealed. The first coat will soak into the canvas or panel and act as its own sizing (sealer). Then subsequent coats are applied in alternating directions across the canvas. To get a very smooth surface you may wish to sand with sandpaper between coats. Some acrylic gessos are designed to have a harder surface specifically so they may be sanded smooth, but as they are less flexible they may crack on a movable surface such as stretched canvas, so should only be used on rigid surfaces.

For oil painting it is especially important that the oil never reaches the substrate as it will rot the canvas, paper or wood. Traditionally oil painters seal the surface with rabbit skin glue and then prime the surface with gesso (glue with chalk). Using these two layers assures that none of the oil will seep through. Some artists who use ready-made stretched canvases will apply an additional layer of acrylic primer to the surface to ensure that it is well sealed.

For painting on paper you may wish to prime both sides of the paper (one after the other dries) as the paper will curl when it is wetted by the primer. Painting the other side then un-curls it. For oil paint on paper you may want at least three coats.

Priming your painting surface is part of properly creating a painting. The underlying structure is very important to the longevity of the painting as well as to the appearance. Primer creates a surface that is sealed just enough to prevent the paint seeping through to the substrate (canvas, paper, wood), but is absorbent enough to hold onto the paint. If you were to paint on an unusual surface like a rubber toy, the paint might not adhere properly. But if you prime the surface with acrylic gesso/primer first, then your paint will go on properly and stay on. The primer is stickier than paint and will glue the chalk to your substrate and create a better surface to paint on.

While the gesso/primer is wet it may leach colour up from the substrate and cause discoloration to the whiteness of the gesso. The glues in plywood, the resins in wood panels and in stretcher bars may be water-extractable. Sealing the wood or canvas first with a sealant medium such as Golden Acrylic’s GAC 100 will prevent Support Induced Discoloration (SID). Sealing (sizing) with rabbit skin glue does the same thing if you are using genuine gesso. Then prime as normal.

Some artists prefer that the substrate shows through underneath the paint and so they use a clear primer. This is usually an acrylic matte medium. This is a thick white liquid that dries clear so you can see the canvas. The texture is very different to gesso since it does not have the chalk powder in it, the surface is smooth and not as absorbent.

Be warned that priming can be a messy business. Gesso/acrylic primer dries quickly on brushes and can stain clothes. Be sure to use drop cloths and wash everything as soon as possible.

Many artists use the word gesso as a verb meaning “to prime” as in “I will be spending the day gessoing canvases in the studio”.

Some artists mix gesso in with their paint as a painting material.


An application of transparent colour over already dry paint. In acrylic painting all clear acrylic mediums can be used to increase the transparency, flow and suitability of your colour mixes for glazing techniques.


A surface that is shiny when dry is said to be gloss. Some oil paints appear more gloss than others depending on the size of pigment particles and their concentration in the oil binder. Gloss can be increased by using a medium when painting (most mediums, with the exception of those designed to thicken paint, such as beeswax, appear gloss when dry). A popular oil painting medium to use that will increase gloss is a mixture of linseed oil and retouching varnish, diluted with solvent.


A term often used to describe a prepared surface ready for oil painting. The word ‘ground’ could refer to anything from a primed piece of canvas to an aluminium sheet.
A painting ground is the surface onto which you paint. It can be anything.
It is usually on top of a sealant/sizing layer of the surface.
To be structurally sound it should be compatible with both the underlying support and the paint that is going onto it. Just a reminder that an artist concerned with the permanence of his/her paintings should be as concerned with the proper preparation of the foundation layers of the painting that are perhaps not visible (the support, the size and the ground) as the layers they do see (the paint, mediums and varnish).
The ground is required both to give a suitable surface texture and also to give an opaque colour, to cover the canvas or panel colour with white or a tinted ground, or occasionally a dark colour.

Acrylic primer (less correctly called acrylic gesso) is an example of a ground that is also a size. It does both jobs, sealing the substrate and providing a good surface on which to paint oils or acrylics. Genuine gesso is a painting ground for oil paint and egg tempera in particular, but any paint can be used on it. An oil ground is oil paint painted on top of a sizing over the entire surface to prepare the surface for painting with oil colours. So using an oil primer means you cannot paint on that ground with acrylics as the ground will repel the paint.

Painting with soft pastels requires a ground with a tooth to pick up and hold the pigment particles. This toothy pastel ground can be painted onto paper, canvas or panels, or surfaces can be purchased with the ground already applied to them.

To create an absorbent paper-like surface on canvas or panels for painting with watercolours, Absorbent Ground can be used. It is painted onto sized or primed canvas or panels. It is the ground, not the size and the substrate must be sealed first.

Heavy Body

Heavy body acrylic paint has a buttery consistency. When used straight from the pot or tube impasto effects can be achieved and brush marks will retain in the paint. The consistency and characteristics can be manipulated with the use of acrylic mediums.


A hue is the actual appearance of a colour, i.e. you might describe a river to have a greenish brown hue. But it is also put at the end of the name of colours found in paint ranges where the colour is made from a mixture of pigments that have been combined to replicate a genuine pigment. Paint makers will do this to offer a less expensive alternative to the genuine pigment. Mixing with ‘hue’ colours may result in noticeably different results to the mixes achieved with the genuine versions of the same colours.


A term to describe paint that has been applied thickly to a support. Oil paint applied straight from a tube in impasto marks will take a very long time to dry. The drying time can be reduced by combining the paint with a thickening medium such as beeswax or an alkyd impasto alternative.


In italian ‘imprimatura’ means ‘the first layer’. In painting it refers to a thin transparent layer of colour that is laid on to a ground evenly in order to colour it. The layer is thinned with solvent or with a fast drying medium. It is then left to dry before the actual painting of the picture begins. Many artists will leave patches of the imprimatura layer showing through in their work. It is an alternative preparation to a tinted or coloured ground, where the primer is mixed with a colour prior to application to a support.


Intereference colour paint is dual-colour and possesses reflective properties and visible interplay with light. The result of this is that a certain colour will appear at a certain angle, and its complementary will appear at another angle. This causes a shimmering quality. Interference colours are very transparent and work well in glazing techniques.


Interlocking describes the way the hairs are arranged in a good brush. The hairs are interlocked in the ferrule so that as they protrude out from the ferrule the natural curve of each hair helps to form a brush head shape that will maximise the liquid holding capacity of the brush, as well as keep a fine point or sharp square or curved edge.


Iridescent colours have a pearlescent or metallic like quality. The finest metal coated mica particles give the paint its unique metallic sheen.


Refers to the stability of a pigment when exposed to prolonged periods of ultra violet, found in natural sunlight. It is measured using the Blue Wool Scale in the UK, and ASTM in America. Permanence takes into consideration the effects of other elements on the stability and appearance of pigments, including humidity, light, heat, water, acidity, alkali levels etc. The permanence of a paint will be indicated on the label using a rating system determined by the manufacturer and explained in the manufacturer’s colour chart or on their website.


A natural fabric made from long threads woven together which is stronger and more elastic than cotton duck. It is usually darker than cotton duck and can be stretched on a frame, glued on to a board or panel or painted on unstretched. Linen needs to be sized with rabbit skin glue or an acrylic substitute prior to painting with oils. Linens are available in a range of weights (the heavier the weight the tougher the fabric will be) as well as a range of weaves, from fine to coarse. Which you choose will impact on the overall look of your painting.

Mahl Stick

Mahlstick is from the Dutch for ‘painter’s stick’. A stick made from wood or aluminium with a leather bound cushion at one end. A mahl stick is designed to keep your hand steady when painting intricate passages. Rest the stick against one edge of your canvas and hold in place while resting your painting hand against the stick in the position you want to paint in. A mahl stick is helpful in ensuring that you do not smudge drying paint as you work.

The Mahl Stick is a classic tool that hasn’t changed much over the years because it doesn’t need to. It performs the function of a ‘bridge’ over your drawing or painting on which you can steady your hand to perform accurate work. It is the difference between writing with the heel of your palm on the table or writing with your whole hand in the air. The bracing action gives you control but you don’t smudge or smear your artwork because your hand doesn’t rest on the work. The mahl stick we have at Jackson’s is a sturdy metal rod almost a metre long with a padded end. The stick is made of lightweight but sturdy aluminium and the suede covered cork end has a bit of friction so it won’t slip around easily. It unscrews into 2 parts for portability and storage.

The usual way that artists use it is to hold the mahl stick with your non-dominate hand, propping the padded end of the stick on the table if drawing flat or on the edge of the canvas, easel or wall if painting vertically, or on a dry part of your painting – and positioning the rod above the area that you need to reach. Then brace the heel of the hand that is holding the pencil or paintbrush on the rod, lower it to the height you need and make your marks. You can adjust the stick during the drawing and painting if you need to get closer or further away. With practise you can control the end of the mahl stick with just two fingers and so still hold a palette as well with your non-painting hand.

Tip: If you cannot find a suitable position for the resting end because the work is raised above the surface so the end of the stick will be too low you can build an instant raised structure with a tub of paint or tin of soup or the like to act as the other side of your ‘bridge’.

Mass Tone

How the colour of a paint looks when it is squeezed from a tube into a condensed ‘blob’.


Also spelled ‘matte’. A complete lack of shine on the surface, the opposite of gloss.


An additive that is mixed with paint in order to extend the colour or alter some of its properties such as consistency, texture, transparency and drying time.

Mica Flake

Mica is the sparly flakes of mineral that glitter in granite. These flakes are used in iridescent acrylic paints and mediums. Mica flakes of all different degrees of coarseness are used in acrylic paints and mediums.

Milling or Mulling

Milling is the process of dispersing the pigments into the binder (in oil painting this is usually linseed oil, but could also be safflower, poppy or walnut oil). It is usually done with a glass muller on a slab.


The use of only one colour in a painting, which is likely to appear in a range of differing tonal values.


A feature within a composition.


A wide flat brush that can evenly apply paint or varnish.

Moulding Paste

Moulding (or molding) paste is a white opaque acrylic paste that can be used to build surface layers and create texture on a painting surface. It can be tinted with acrylic colour or applied on its own, left to dry and then painted afterwards. It dries hard yet flexible.

Open Acrylic

Open acrylics are slow drying acrylic paints which allow for painting approaches that were previously only possible in oil paint.

Open Time

The length of time in which it is possible for a brush to move applied paint around on a surface before it dries. Also used for the time a gilding size (adhesive) stays sticky for metal leaf application.


Can refer to a surface on to which you mix your colours, or the selection of colours an artist has chosen for their painting, e.g. ‘the painting had a palette of mauves and greens’. Suitable painting palettes for acrylic paint are usually made from plastic. They come in a variety of shapes and sizes. Some are designed to be held as the artist is painting and will have a thumb hole, others are designed to be placed on a table.

Palette Knife

Palette Knives are also known as painting knives and are used by painters to mix colour and apply paint to a support. They are usually made from plastic or forged stainless steel. They are easy to wipe clean with a rag which means it is easy to keep colour mixes clean as well. As a painting tool it is ideal for impasto technique and also for applying colour in a flat and uniform layer.


A rigid painting surface for acrylics, oils, encaustic, pastels or watercolours. Made from solid wood, plywood, mdf, compressed card or aluminium. They are often braced to prevent warping both during the priming and painting period and over time. May also be wood with canvas or paper adhered to the front. Especially useful for encaustic or oil painting where a rigid surface helps prevent cracking of the paint surface over time.


Watercolour Papers

Watercolour paper has a “hard size” on top of the paper that allows the water to penetrate and the pigment to remain on the surface. This gives the painting its brilliance and also allows for corrections.

Watercolour paper comes in different textures. ‘Hot Press’ (HP) is the smoothest, it is also a bit less absorbent as it has been compressed to a harder surface. ‘Not’ (also called cold pressed) has a medium textured surface and is the most popular finish, it is especially good for beginners. ‘Rough’ is highly textured paper and is the most absorbent. Botanical artists often prefer hot pressed paper as the smoothness allows them to be very accurate in their rendering.
The weights of the papers range from 90 lb to 400 lb. The heavier the weight of the watercolour paper the less the paper will buckle when wet. For lighter weight papers (140lb and below) the paper is usually stretched (wetted and laid out on a board and taped down with gum-strip tape, or you can use a specially designed paper stretcher device like the Keba Artmate).
Watercolour papers can vary in whiteness from bright white to a creamy off-white and are available in tinted colours.

Watercolour papers come in sheets, pads, rolls, and blocks. Blocks are pads of pre-stretched paper that are glued on all four sides except for a small space on one side. This allows for painting without stretching and when the painting is dry you can remove the top painted sheet by running a butter knife around the edge from the gap in the side.

Drawing Papers

Cartridge paper is a high quality type of heavy paper used for illustration and drawing. It comes in a variety of smooth textures. It is available in loose sheets, pads (glued or spiral), hardbound and softbound sketchbooks and rolls.
Bristol paper is a strong and durable, all-purpose drawing paper. It has a very hard surface that is heavily sized, polished, and compressed. It is also used for airbrushing.
Other papers that are suitable for drawing include the very popular Stonehenge paper.

Pastel Papers

Pastel paper is used for soft and hard pastels and charcoal. It is usually coloured paper, with the colour chosen being very important as it will be a major component of the finished work. It comes in a few different textures, all with some amount of tooth or weave that will catch hold of the pastel particles. Ingres is a laid paper with a mesh imprint from a screen. Random texture gets its surface from a cloth matt imprint, similar to Not texture watercolour paper. There are a few types with toothy textures from ground cork or sand that are similar to sandpaper. A few come with the colour screenprinted on and some are waterproof for working the pastels with water. Paper for oil pastels is hard and white and usually comes in a pad with glassine paper interleaving to protect it from smudging.

Oil and Acrylic Painting Papers

These medium to heavyweight papers are usually canvas textured and primed for painting with either oil or acrylic. Most of the papers prepared for acrylic paint are universally primed to accept both oil and acrylic. Paper must be sealed completely if painting with oil paints because the oil will separate out if the paper is absorbent and form a halo of oil around the colours and it will also rot the paper over time. Although acrylic paint can be used on any paper, acrylic painting paper is usually designed to mimic canvas or it is very heavyweight. Oil and acrylic painting papers are especially useful for taking to classes or using in the field and are an economical choice for making a study or sketch prior to the major work on canvas.
You can also get sheets of primed actual canvas (as opposed to the canvas-textured paper) in pads.

Fine Art Digital Papers

Inkjet papers that allow high quality reproductions of your artwork or prints of your digitally designed original prints come in a wide variety of textures and weights. They are coated to accept inkjet inks. They can be sprayed with an inkjet fixative to prevent smudging if that is a problem. They are archival. Sheets of primed canvas designed to go through your inkjet printer are also available.

Paste (acrylic)

A thick, white opaque medium that can be tinted with acrylic colour or used on its own on to a support to build up texture and impasto marks. There are a number of different acrylic pastes available with a variety of consistencies and textures/characteristics.


Working with pastels is usually called pastel painting. It is a way for artists to paint directly with pigment without the intermediary of a brush. Blending can be done with the finger, blending tools or a brush. Pastels come as oil pastels, soft pastels and hard pastels. Health concerns about breathing in dust from the soft chalk pastels have caused some pastel artists to switch to oil pastels.

An oil pastel has the pigment bound with non-drying oil and wax. Quite different results can be achieved using a variety of techniques. For example: oil pastels dissolved with solvents look very different to ones used lightly over the surface of a textured paper. Some wax or oil pastels are also water-soluble. Some artists use fixative to protect the work as the colour remains somewhat smudge-able but mounting and framing behind glass is usually sufficient protection from smudging.

soft pastel is made to be as soft as possible without falling apart or breaking too easily. The surfaces used with soft pastels usually need to have a tooth to hold the powdery colour onto the surface. Because colours are mixed on the surface and not mixed on a palette beforehand pastels usually come in a huge range of tints and shades of colours. Finished paintings should be sprayed with a fixative for longevity as the soft colour may not adhere completely to the surface (especially if many layers are built up) and framed with a mount and glass to protect the work, though some artists do not like the look of fixative and simply frame the work. Soft pastels can be used dry or with water and also come in a pencil format that is tidier to use.

Hard pastels are usually square and are often called carre crayons. They have been baked at a higher temperature and their hardness allows finer lines to be made with their edges. Like all artist materials the quality of a pastel is measured by the amount and quality of pigment and the higher quality pastels have little or no filler and the minimum amount of binder required to hold the pastel together.

Every artist develops a preference for a particular brand, often based on colour choice or level of softness or hardness. A beginner would be wise to buy a colour in each brand and as they need to replace each colour buy the brand they have come to like best. Pastel painting is usually done on pastel paper, which comes in a variety of colours and textures, though there is a textured ground for pastels by Golden Acrylics that can be painted on primed wood or canvas so that those surfaces can hold the pigment from soft pastels.


Permanence takes into consideration all factors that may influence the stability and appearance of pigments, including exposure to UV rays, humidity, heat, water, acidity, alkali levels etc. The permanence of a paint will be indicated on the label using a rating system determined by the manufacturer and explained in the manufacturer’s colour chart or on their website. Some manufacturers say permanence when they mean lightfastness (which only considers UV), so it’s worth double checking if this is of particular concern.


Pigments don’t just give paint its colour. They will also alter how the paint behaves as you work. Tinting strength, opacity, granulation and other handling properties are all a result of the pigments used in a paint, and when different brands produce even the most familiar colours to numerous varying recipes, it’s best not to rely on titles alone.
Pigment numbers are grouped into 9 categories, each prefixed with a code that will help you
decode how your colours are made. These codes are PR, PO, PY, PG, PB, PV, PBr, PBk and PW, and refer to red, orange, yellow, green, blue, violet, brown, black and white respectively.

Some pigments will crop up again and again across a colour chart; PBr7 represents the natural iron oxide used to produce raw and burnt umbers and siennas. Others will appear in variations, either denoted by a colon and a secondary figure such as PW6:1 for buff titanium derived from PW6 titanium white, or listed in brackets after as in PV23 (RS), a Red Shade of the Dioxazine Violet pigment. It can be useful to look at the paints you use most often and make a list of your preferred pigments, especially when considering purchasing from new brands.

While there are plenty of good reasons for a manufacturer to mix pigments, painters will often prefer to use colours with one pigment when possible. Single pigment paints are more predictable in mixes and tints, whereas a paint made from multiple colour components might create unexpected combinations on your palette. Still, mixes can be beneficial. They are commonly used in the production of hues, convenient replacements for dangerous or expensive pigments and are often the only form in which defunct historical colours can be found.

Pigment Load

Pigment load refers to the ratio of pigment to binder in a paint.

Plein Air

To paint out of doors in front of the subject. Famous artists who painted en plein air include Pisarro and Renoir.


A pochade box will open up to hold a small painting panel in place, and can also transport tubes of paint, medium, brushes and a palette. They are most commonly used for painting en plein air. The pochade box will usually have space for carrying wet panels in them without smudging one another, and will fix on to a tripod to position at the right height for painting.

Polymer Medium

Extends colour and increases transparency and gloss as well as increasing film integrity. It is particularly useful in making acrylic glazes.

Primary Colours

The traditional primary colours for painting are Red, Yellow and Blue. They are used because they can produce the largest range of colours around the spectrum. Other triads, such as Cyan, Yellow and Magenta are also used, producing gamuts of different intensities. A split primary palette will include warm and cool versions of each colour.


A surfacing material used to coat a support to get it ready for paint application. Acrylic primer is made from calcium carbonate suspended in an acrylic binder. It can be applied directly to a support without the need for a prior application application of size. To create a very smooth surface apply 2- 3 coats and allow to dry fully and lightly sand between applications. Gesso is a more absorbent variety of primer. Multiple coats of acrylic gesso will increase the absorbency of the surface, and light sanding between layers will optimise the smoothness.

Acrylic primer varies a lot in quality and poor quality products can provide a less absorbent ground than is often preferred. Good quality acrylic primer (can contain upwards of 14 ingredients) is a very good product for both oil painting and acrylic painting. It does both steps of the surface preparation in one- it both sizes (seals) the surface and gives a ground for painting.

Priming Brush

Usually a flat wide brush, made with synthetic or hog hair. For an even application, load the brush and apply whilst holding it at around 45 degrees to the support. Brush the primer on in all directions to make the coverage even. Allow each layer to dry fully before applying the next layer.

Printmaking in Acrylic

Acrylic printmaking inks will dry more quickly than oil based inks, which can work to both one’s advantage as well as disadvantage. Acrylic paint can be used in relief and screen printing with the aid of special printmaking mediums – without these the paint may dry too quickly and will not have the best consistency for successful printmaking.

Print Rack

A Print Rack or Print Browser is used for storage or display of works on paper. Useful at art fairs for buyers to browse through the work these can be table top of floor-standing displays. Often the work is placed in a poly bag with a stiff card for protection and the work on paper is flipped through like at a record shop.

Pumice Gel (acrylic)

Pumice gel is available in a variety of textures, from fine to extra coarse. When dry this opaque white gel dries to a concrete like surface, mottled with craters, just like pumice stone. The fine pumice gel is particularly useful as a drawing ground. As with other white opaque acrylic mediums, pumice gel can be tinted with acrylic colour or applied on its own.

Rabbit Skin Glue

A strong glue made from animal parts, that is an ingredient in genuine gesso, is used for sealing (sizing) panels and canvas before priming and is used as sizing for papers. It stiffens canvas in preparation for gesso primer in oil painting. Also called hide glue.

For preparing canvas and panels the usual method is to soak the pellets or powder overnight, the next day heat in a double boiler and brush onto the canvas while still warm (do not overheat as the glue will be weak). Two coats are preferred to seal the canvas well, the first being scrubbed into the canvas to get well into the weave. Discard any left over as it does not re-heat well. Then prime the surface as normal.


A clear acrylic medium that will slow the drying time of acrylic paint.

Scaling Up/Down

The process of transferring a composition from one surface to another. To scale up is to transfer and enlarge the image, and to scale down is to transfer and reduce the image. To do this a grid is placed over the top of the original composition. The same number of squares are drawn on to the surface you are transferring to. The artist will then carefully match the drawing in each square to the original. A projector can also be used to scale up or down without the need for a grid.


Applying opaque or semi opaque colour over the top of already painted areas, in a ‘broken brushmark’, i.e., the scumbled mark will be uneven and only cover some of layer of paint underneath. Scumbling will add depth and texture to your painting.


Painting thin glazes to give a misty effect to areas of a painting. For example sfumato might help to push some mountains on the horizon in a landscape painting further into the distance.


To paint or draw at the exact scale that you see the subject. Holding a pencil or paintbrush up at arms length against the subject helps to establish at what size you actually see the elements of your composition, and compare lengths and sizes with one another.

Sinking In (oil painting)

When paint is absorbed by the surface it has been applied to and the colours appear less saturated than when they were first applied. This can sometimes cause some areas of the painting to appear more shiny and colour filled than others, as often there are inconsistencies in the absorbency of a surface, which affects the varying degrees of ‘sinking in’ on a surface.


The speed at which the hairs of a brush will ‘snap’ back into place if held away from its natural position from the ferrule. Many artists look for good snap in their brushes as it means the brush will make sharper, more vibrant looking brush marks.

Spray Acrylic

Spray paint enables you to apply acrylic colour in thin and even layers. As the paint is dispersed in tiny droplets it tends to dry more quickly than if applied with a brush (within minutes). Colours are easy to blend with one another. Professional acrylic sprays will have low pressure handling, this means that the artist has a greater degree of control over the paint application.

Stay Wet Palette

Stay wet palettes are usually made of plastic and are lined with a sheet of paper that feels a bit like greaseproof paper, which helps keep the paint wet for longer. Keeping the lid on the palette will also reduce the amount of air getting to the paint to help keep it wet for longer. Refill packs of the paper to line the palette are available.

Stretched/Unstretched Canvas

A piece of linen, hessian or cotton duck that has been tightly wrapped around a frame made of wood or aluminium and fixed at the back.Sizing and priming the stretched canvas will increase the tension in the stretch. This creates a vibrant, drum like surface to paint on. Stretched linen and cotton duck canvases can be bought ready made. They are available unprimed or primed with acrylic or oil primer. Unstretched canvas can be purchased from and by the roll, ready to be stretched on to a frame at home or worked on unstretched.

Stretcher Bars

Stretcher bars will assemble to make a frame onto which canvas can be stretched over. They are available in pairs and made of wood or aluminium.


A general term for a surface ready to be painted on. A support can be anything from a canvas to a wooden panel.

Synthetic Brushes

Synthetic brushes often replicate the characteristics of traditional, natural hair painting brushes, such as those made from hog or sable. They are known to be resilient and easier to clean (as the hairs are less absorbent than natural hair). Not all synthetic hair is the same and so characteristics vary across brands.


Tacks are a similar shape to drawing pins and are made of metal, and are used to fix canvas to the sides of a stretcher bar. Staples are generally considered to be more successful at keeping canvas fixed to the stretcher, but tacks are often still used to add a traditional aesthetic to the overall look of the support.

Tar Gel

A colourless and clear gel that when poured has a stringy consistency. Tar gel is great for pouring over a surface as it will continuously flow, and you can control the thickness of application by how you pour. The gel can be applied clear or can be coloured with fluid acrylic paint.

Tinting Strength

The power of one colour to overpower another colour when mixed together.

Toning a Canvas

Painting on a white canvas can cause you to paint in colours lighter or brighter than you intend that you need to then adjust after you have more of the white covered. To avoid this some artists apply a middle value on the whole canvas before they start, this toning of the canvas also prevents unwanted bits of white canvas showing through your brushwork and you can leave bits of the tone colour showing for added liveliness.


Tooth in acrylic painting usually refers to how coarse a surface feels when dry. Often used to describe the surface quality of gesso, primer and acrylic pastes and mediums.

Transparency / Opacity

The measure of how much light is able to pass through an applied paint and interact with the surface beneath. Transparent paints appear more luminous on a white support because they allow a larger proportion of light to hit the surface they’re laying on, like a filter placed over a light bulb. Opaque paints block this reflection from occurring, and can be used to cover layers of colour underneath. Transparent paints are better suited to glazing techniques, though these can still be achieved with opaque colours if diluted sufficiently or mixed with a suitable medium.


The appearance of a paint when it is spread across a surface in a thin film.


The initial layer of painting, usually executed in a minimal number of colours to establish areas of tone and ‘map out’ the composition on the support.


This term means ‘tone’ in visual art. ‘The value of the object’ is a description of how light or dark the object is. The lightest value is white and the darkest value is black.

Varnish for Acrylic

Acrylic varnishes offer a protective coating to a finished painting, keeping it safe from dust and surface damage (scratches etc.). Some varnishes also have UV light resistors which will prevent colour fade. We recommend applying an isolation coat over your painting prior to varnishing – a soft gloss gel medium would be ideal for this. This will allow for the varnish to be removed in future, if necessary, with no damage risk to the painting itself. Always ensure that you varnish work in a dust and dirt free environment, and remove any dust or dirt from the surface of your work prior to varnishing. Varnish can be applied with a spray or a brush.

Varnishing Brush

A varnishing brush should be kept in good condition and have clean, soft hairs. A square ended brush will make it easier to achieve an even application. A synthetic mottler is a good choice of brush for applying varnish. Several thin layers are better than one thick one. Lean your painting image side down against a wall during the drying process to ensure that dust does not settle on the surface.


Applying a glaze with a semi-opaque paint. A trace of the painting underneath will show through the layer of velatura which acts as a veil.


The weave of a canvas can be completely smooth or very prominent, depending on how it was made. It will have an effect on how your painting looks. Artists who like to explore textures in their work might prefer a coarser weave, whereas artists who paint very fine detail may prefer a finer grain. The set of threads that are aligned lengthways in fabric is known as the warp, and the weft is the set of threads that weave in and out of the warp. In painting it is important that the warp and weft are similar so that when the canvas is stretched it will do so uniformly, without inconsistencies such as wrinkling. This is particularly worth noting if you are working with a linen that was not purchased from an art supplier.

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SOURCEJacksons Art
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