Читать книгу: «Complete Artist’s Manual: The Definitive Guide to Materials and Techniques for Painting and Drawing»

Before starting a painting or drawing, it is worth spending some time choosing and preparing the surface, or support, as this will have a great bearing on which medium you use, and the effects that you are able to achieve with it. Although the range of canvases, panels and papers may seem somewhat bewildering at first glance, finding the right support for your purpose is not very difficult when you understand the properties of each one. A properly prepared support will greatly increase the longevity of a work and, in addition, you can derive a lot of pleasure and satisfaction from this aspect of the artist’s work.

Linen is considered the best canvas because it has a fine, even grain that is free of knots and is a pleasure to paint on. Although expensive, it is very durable and, once stretched on a frame, retains its tautness. Good-quality linen has a tight weave of even threads which will persist through several layers of primer and paint; avoid cheap linen, which is loosely woven.

Preparing linen canvas

The weaving process makes raw linen canvas prone to shrinking and warping when it is stretched, and it has a tendency to resist the application of size. However, both these problems can be solved by temporarily stretching the canvas, wetting it and allowing it to dry. Then remove the canvas from the stretcher bars and re-stretch it; this second stretching creates a more even tension across the cloth.

Cotton canvas

A good-quality 410–510gsm (12–15oz) cotton duck is the best alternative to linen, and is much cheaper. Cotton weaves of below 410gsm (12oz) are fine for experimenting with, but they stretch much more than linen and, once stretched, they are susceptible to fluctuations in tension in either humid or dry conditions. The weave of cheap cotton quickly becomes obscured by layers of primer and paint, leaving the surface rather flat and characterless.

Hessian

Hessian is inexpensive, but has a very coarse weave and requires a lot of priming. It is liable to become brittle and lifeless in time.

Synthetic fibres

Synthetic fabrics, such as rayon and polyester, are now used in the manufacture of artists’ canvas. These canvases come ready-prepared with acrylic primer and are worth trying out, as they are exceptionally strong and durable, flexible but stable, and resistant to chemical reaction.

Canvas textures

If you use bold, heavy brushstrokes, canvas with a coarsely woven texture is the most suitable. A smooth, finely woven texture is more suited to fine, detailed brushwork. Another consideration is the scale of your painting. A fine-grained canvas is best for small works, as the texture of coarse-grained canvas may be too insistent and detract from the painting.

Ready-primed canvas

Ready-primed canvas comes prepared with either an oil- or an acrylic-based primer. It is better to use an oil-primed canvas for oil painting and leave acrylic-primed ones for acrylic paintings, but you can use an acrylic-primed canvas for oils if you paint thinly and on a small scale.

Canvas may be single- or double-primed. The latter is more expensive; it has a denser surface, but it is less flexible than single-primed canvas.

Canvas weights

Wet the stretched linen canvas and allow it to dry.

The weight of canvas is measured in grams per square metre (gsm) or ounces per square yard (oz). The higher the number, the greater density of threads. Better-grade cotton canvas, known as cotton duck, comes in 410gsm (12oz) and 510gsm (15oz) grades. Lighterweight canvases of between 268gsm (8oz) and 410gsm (12oz) are recommended for practice only.

Ready-prepared supports

You can buy ready-primed and stretched supports which consist of a piece of canvas mounted on a stretcher. These supports are convenient, but are expensive when compared to the cost of stretching, sizing and priming your own canvas.

Popular artist’s canvases

1 Ready-primed cotton-rayon mix

2 Ready-primed cotton duck

3 Ready-primed artist’s linen

4 Superfine artist’s linen

5 Cotton duck

6 Flax canvas

7 Cotton and jute twill

Buying economically

Before buying lengths of canvas, work out how you will divide up the fabric to make as many pictures as possible with the minimum of wastage (canvas rolls come in several widths). When doing your calculations, don’t forget to allow a 50mm (2in) overlap all round each picture for attaching the canvas to the stretcher.

Acrylic and oil don’t mix

Most of the ready-prepared canvases and boards available in art shops are primed for use with oil or acrylic paint. If you paint in acrylics, take care not to buy supports which are prepared specifically for oils. The linseed oil in the primer repels acrylics, and the paint eventually comes away from the support.

Canvas texture

The formal elegance of this abstract painting is enhanced by the subtle texture of the linen canvas, which appears through the thin layers of oil paint.

Pádraig Macmiadhachain

Blue Morning

Oil on canvas

25 × 30cm (10 × 12in)

Overlap

Remember to add a minimum of 50mm (2in) of canvas all round, for when you attach it to the stretcher.

SEE ALSO

STRETCHING CANVAS

SIZING FOR OILS

PRIMING

OIL PAINTS

ACRYLIC PAINTS

Stretcher bars

Wooden stretcher bars are sold in most art-supply stores and come in different lengths. They have premitred corners with slot-and-tenon joints. The face side of each stretcher bar is bevelled to prevent the inner edge of the stretcher creating ‘ridge’ lines on the canvas. Stretcher bars come in varying widths and thicknesses, depending on the size of support you wish to make. For a work under 60 × 60cm (24 × 24in), use 45 × 16mm (1¾× ⁵/₈in) stretcher bars. For larger works, use 57 × 18mm (2¼ × ¾in) bars.

Wedges

You will also need eight wedges or ‘keys’ for each stretcher. These fit into slots on the inside of each corner of the assembled stretcher; if the canvas sags at a later date, the wedges can be driven in further with a hammer to expand the corners and make the canvas taut again.

Canvas-straining pliers

Canvas-straining pliers are especially useful for stretching ready-primed canvases. They grip the fabric firmly without any risk of tearing, and the lower jaw is bevelled to give good leverage when pulling fabric over a stretcher bar; the correct tension is achieved by lowering the wrist as the canvas passes over the back of the frame.

Other equipment

Use a heavy-duty staple gun and non-rusting staples with a depth of at least 10mm (³/₈in) to fix the canvas to the frame. You will also need a rule or tape, a pencil and a pair of scissors to measure and cut out the canvas; a wooden mallet to tap the stretcher bars together; and a T-square to check that the frame is square (or you can use a length of string to ensure that the diagonal measurements between the corners are the same).

Large canvases

A support that is larger than 80 × 100cm (32 × 40in) will require an extra crossbar between the two longest sides, to support them when the canvas contracts during preparation, exerting a great deal of force.

Tacks

Using a hammer and non-rusting tin tacks to fix the canvas to the frame is more economical than stapling, but means more work.

Pliers

Canvas-straining pliers stretch ready-primed canvases firmly and without tearing.

Cutting the canvas

Use pinking shears to cut canvas; they avoid the need to fold the edges over at the back of the frame to prevent the canvas fraying.

Assembling the stretcher frame

Slot the stretcher bars together, checking that all the bevelled edges are at the front. Tap the corners gently with a wooden mallet or a piece of wood for a close fit.

Checking for square

Use a T-square to check that all the corners of the assembled frame make right angles. Double-check by measuring the diagonals with an expanding tape measure or a length of string; they should be of equal length. If the frame is out of true, correct it by gently tapping the corners with the mallet.

Stretching the canvas

(1) Cutting out the canvas

Working on a large table or the floor, lay the frame bevel-side down on a piece of canvas. Cut the canvas to fit the frame, allowing a margin of about 5Omm (2in) all round for stapling (1).

(2) Securing with the first staple

Ensure that the warp and weft threads of the canvas run parallel with the sides of the frame. Fold the canvas round to the back, and secure with a staple at the centre of one long stretcher bar (2).

(3) Tensioning the canvas

(4) Continuing to staple

Reverse the frame, pull the canvas firmly and evenly, and secure a staple opposite the first one so that consistent straining is obtained. You can use canvas-straining pliers, if necessary, to grip the cloth and pull it taut over the frame (3). If glue size is to be applied, the canvas should be taut, but not as tight as a drum, to allow for possible shrinkage. Repeat the process on the two short sides, so that one staple holds the canvas to the centre of each stretcher bar (4). Check the parallel alignment of the canvas weave.

Securing the canvas

(5) Stretching and stapling

Now add two more staples to each of the four stretcher bars – one on either side of the centre staples – following the sequence shown in the diagram (5). The staples should be evenly spaced at 50mm (2in) intervals. Continue adding pairs of staples to each side, gradually working towards the corners. Insert the final staples about 50mm (2in) from each corner. Note that working systematically out to the corners keeps each side in step with the others. Fastening the canvas completely on one side before doing the next stretches the canvas unevenly.

Finishing off

(6) Fixing the first corner staple

(7) Folding the flaps

(8) The finished corner

(9) Inserting the wedges

The corners should always be finished off neatly; if they are too bulky you will have difficulty in framing the picture. Pull the canvas tightly across one corner of the stretcher, and fix with a staple (6). Then tuck in the flaps on either side smoothly and neatly (7) and fix with staples. Take care not to staple across the mitre join, as this will make it impossible to tighten the canvas later on. Then fix the diagonally opposite corner, followed by the remaining two. If necessary, hammer the folds flat to produce a neat corner (8). Finally, insert two wedges in the slots provided in each of the inner corners of the frame; for correct fit, the longest side of each wedge should lie alongside the frame (9). Tap the wedges home very lightly. The canvas is now ready for sizing and priming.

SEE ALSO

CANVAS

SIZING FOR OILS

Wood panels

Wood, for centuries the traditional support for oil and tempera painting, can no longer be relied upon to be well seasoned, so it tends to split and warp. It is also heavy to transport, and is now largely superseded by economical composition boards.

Hardboard (Masonite)

Hardboard is inexpensive, strong and lightweight. It is available in two forms: tempered and untempered. The tempered variety is suitable for oil paints and primers, and it does not require sizing. For acrylic painting, however, use untempered board, which has no greasy residue. Sundeala board, grade ‘A’, is particularly recommended, as it is lightweight and its surface is slightly more porous than standard hardboard, giving a good key for size and primer.

Hardboard has one smooth and one rough side; the smooth side is the one most often used. The rough side has a texture which resembles coarse canvas, but it is only suitable for heavy impasto work, as the texture is very mechanical and over-regular.

Hardboard is prone to warping, particularly in humid climates, but this risk is reduced by priming the front, back and edges of the board. Paintings larger than 45cm (18in) square should additionally be braced with a framework of wood battening across the back (see here).

Plywood

Plywood comes in various thicknesses and has smooth surfaces. It does not crack, but it can warp. To keep the sheet stable, size and prime it on the front, back and edges. Large sheets should be battened or ‘cradled’ by gluing wooden battens to the back of the board (see here).

Chipboard

Chipboard is made from wood particles compressed into a rigid panel with resin glue. Thick panels of chipboard are a sound support as they do not crack or warp and don’t require cradling, but they are heavy to transport. Another disadvantage is that the corners and edges may crumble, and, being absorbent, they need to be well primed.

Medium-density fibreboard (MDF)

MDF is made from pressed wood fibre and is available in a wide range of thicknesses and in standard board sizes. It is a dense, heavy, but very stable material and has fine, smooth surfaces. MDF is easily cut by hand or with machine tools. Large, thin panels may need to be cradled to help keep them flat (see here).

Cardboard

Degas and Toulouse-Lautrec painted on unprimed cardboard on occasions; they used its warm brown colour as a middle tone, and produced a matt, pastellike effect on the absorbent surface. However, a finished painting must be framed under glass if it is to last. Cardboard must be sized on both sides and on the edges to prevent warping and to stop impurities in the cardboard from leaching into the paint.

Mount board

Heavy mount board, or pasteboard, is available in a range of colours and has a smooth surface suitable for painting in acrylics and gouache, particularly when thin washes and glazes are applied. It is also used for pen-and-ink drawing. Always choose conservation board for work that is intended to last, as this is guaranteed acid-free.

Watercolour board

Watercolour board consists of a solid core faced with good-quality watercolour paper. The board provides extra strength and stability, and dispenses with the need for stretching paper prior to painting. Check that the core of the board, as well as the paper, is acid-free. Watercolour boards also perform well with pastel and charcoal.

Pastel board

Pastel paper mounted on board is available in a range of sizes, colours and finishes, from soft velour to a high-tooth, abrasive surface.

Canvas boards and panels

Commercially prepared canvas boards and panels consist of acrylic-primed cotton canvas mounted on rigid board. They come in a range of standard sizes and surface textures, and are a good choice for beginners. Because they are compact and lightweight, they are ideal for painting outdoors. Cheaper-quality canvas boards with an imitation canvas surface have an unsympathetic, mechanical texture and a rather slippery surface priming, and the backing board is prone to warping.

Marouflaging board

Many artists prepare their own canvas boards by covering boards with canvas or muslin – a method known as marouflaging. Fabric glued to board provides a surface which combines the unique feel of working on canvas with the greater stability of a firm surface which is not prone to movement under atmospheric changes. Any natural fabric can be used, such as worn linen, cotton sheets or tablecloths, unbleached calico, butter muslin or canvas offcuts.

Method

Check that the board is cut square and true. Dress the edges and lightly sand the smooth side to provide a key for the glue. Brush away all sawdust. Lay the board over the fabric, then cut the fabric to size, allowing a 50mm (2in) overlap all round (1).

With a household paint brush, apply size to the face and edges of the board (2). Smooth the fabric over the board with an equal overlap all round (3). Ensure that the warp and weft threads lie straight and parallel with the edges, as any distortion in the weave will show in the finished picture and be visibly distracting.

Apply more size to the cloth, brushing from the centre outwards and smoothing out any creases or air bubbles. When the size has dried, turn the board over and trim across the corners (4).

Size a margin around the edge of the reverse of the board, wide enough to stick down the overlapped cloth, which should not be pulled too tight as it may cause the board to warp. Smooth down the flaps of material and fold the corners over neatly (5). Add a final coat of glue over the reverse side to prevent warping. Leave to dry flat overnight before priming.

Keying hardboard

Before painting on the smooth side of hardboard, lightly sand the surface to provide a key for the application of primer.

Preparing a panel

To save time, an artist will periodically prepare a batch of panels at once, all cut from one sheet of board. For example, from a sheet of hardboard measuring 120 × 240cm (4 × 8ft) you can cut thirty-two 30.5 × 30.5cm (12 × 12in) panels, or thirty-eight 25.5 × 30.5cm (10 × 12in) panels. Most timber yards cut board for a small fee, or you can cut it yourself.

Cutting panels

Mark out the sheet with a rule and pencil, making sure all the corners are square, and saw along these lines. Now ‘dress’ the edges of each panel with a sanding block to remove any burrs from the saw cuts. To provide a key for the size or priming coat, lightly sand the surface of each panel. Always use a light touch; too much downward pressure may create depressions in the board.

Cradling boards

Cut two battens 50mm (2in) shorter than the width of the board. Chamfer the ends and then secure the battens to the back of the board, using wood glue for man-made boards, or woodscrews for solid wood or thicker boards.

Gesso panels

Gesso panels are the traditional support for egg-tempera painting. They can also be used for oil, acrylic and watercolour painting, but are quite difficult and time-consuming to prepare. Ready-prepared gesso panels can be bought from specialist art stores, though they are expensive. Gesso panels have an exceptionally smooth, brilliant white finish which particularly enhances the translucence of tempera colours.

Cardboard and hardboard

Cardboard’s warm colour brings a mellow harmony to Toulouse-Lautrec’s oil sketch. Note how the brush drags on the absorbent surface.

Henri de Toulouse-Lautrec (1864–1901)

Woman in Profile (detail)

Oil on cardboard

For his bravura painting, Tom Coates used the reverse side of some unprimed hardboard. There is a lively interplay between thick impastos and thin, drybrushed marks, with the paint catching on the tooth of the board.

Tom Coates

Alfred Daniels Painting

Oil on panel

25 × 20cm (10 × 8in)

Marouflaging a board

(1) Cutting the fabric to size

(2) Applying size to the face and edges

(3) Smoothing the fabric

(4) Trimming the corners

(5) Folding the corner

Priming for oil paint

To provide a sympathetic surface for oil paint, prime a marouflaged board with alkyd or acrylic primer. If you prefer a slightly absorbent, matt surface, thin the primer with white spirit (about 10 per cent by volume).

Time-saving

When making up several small boards, you will find it quicker and easier to glue the fabric to a large piece of board. Leave it to dry and then cut it up into the required number of boards, using a bandsaw As long as the fabric is glued down firmly, it won’t matter that some edges have no overlap.

Preparing canvas board

If you dislike the slippery surface of some commercially primed canvas boards, you can simply apply a further coat of alkyd or acrylic primer, in order to give a more absorbent surface. Matt household paint may be used for sketches or practice work.