1、Ready-made or Pre-stretched canvases:

----Most commonly have a universally primed canvas stretched on to a wooden frame with bevelled edges (so that the edge of the frame does not leave an imprint when the canvas is painted on). Canvas is fixed to the frame with either tacks on the sides, or staples on the back, or both. Canvases are tightly stretched onto a frame, which creates a spring in the fabric when pressure is applied, i.e. when a paint brush applies paint to it. It is generally considered that the more tightly stretched a canvas, the more enjoyable it is to paint on, as the tension in the surface has an element of vibrancy.

2、The surface qualities can profoundly affect some artists’ painting, even more so for techniques like staining in oils or acrylics.

----The canvas is coated with a white acrylic primer, which sufficiently coats the fabric for both oil and acrylic painting. Most ready-made canvases are triple primed (coated 3 times), and some have even more layers of primer. Lots of thin layers of primer is preferable to one thick layer as it is a more stable priming, which is less susceptible to cracking over time, and will be much more likely to be even across the whole surface.

3、Ready-made canvases are available in a range of depths, and if this is of importance to you it is vital to check the dimensions.

----Standard depth canvases are generally considered to look more traditional and are easier to frame, whereas deeper canvases tend to be associated with contemporary or more modern art techniques, although the trends are always changing. This choice is one of pure aesthetics; a standard depth canvas does not perform better or worse than a deep edge or chunky canvas, although thin bars may need to be reinforced with the use of a cross bar for larger sized canvases.

4、There are two major fiber types used to make canvas: cotton and linen (flax).

----Cotton is economical but not as strong as linen, which is easy to stretch and stays tight on the stretcher bars. Linen is made from flax and is stronger because it has longer fibers which means that it is less likely to tear at the staple line or at the sharp outside corner of the stretcher bar. The stiffness of linen means it is harder to pull when stretching and you need to take care to keep even tension across the canvas or it can ripple along the edges later. Linen is also more costly than cotton because it takes many more steps to process the flax fibers and because its inelasticity makes it harder to weave into fabric. Cotton Duck Canvas has more tightly woven threads than plain cotton canvas – the term “duck “comes from the Dutch word for cloth, doek. “Poly-cotton” is an artist’s canvas, it is made for our industry so it has a tighter weave, a finer thread and an overall smoother surface. There is also a super fine texture called “No-Grain” under this category. The addition of polyester means the fabric will not “relax” as much as all cotton and become loose over time.

5、The choice of no grain, extra-fine, fine, medium, rough and extra-rough texture in a canvas affects the feel of painting and the final appearance.

----In addition to choosing the fiber type you also need to consider the weight and the texture of the weave. Similarly to paper, canvas is measured in grams per square meter (gsm) or ounces per square yard (oz). Lightweight fiber have an open weave and generally a fine yarn, they are easier to stretch and are more responsive to tightening procedures. If the canvas has a heavy weight, it is a thick, tough yarn or it is tightly woven. A fine canvas has minimal texture and can be almost smooth, while a rough canvas has a very pronounced weave. A smooth texture is often important to portrait painters as a coarser texture can distort the appearance of skin, so extra-fine linen canvas is sometimes even called Portrait Linen. The ‘No Grain’ texture is almost as smooth as paper and is also great for portraits. The terms ‘super fine’, ‘extra fine’, ‘fine’, ‘medium’, and ‘rough’ refer to the texture of the weave, not the weight. Texture is not necessarily a guide to weight.

6、Unprimed canvas can be considered light-weight at about 5oz (140g); medium weight at about 8oz (230g); heavy weight at about 10oz (280g) or more.

----The heavier the weight the more tension the canvas fabric can take without tearing, so for very large stretched canvases you might wish to choose a heavier canvas. Weight is how much fabric there is per area so it is determined by both thickness of the thread used to weave and how tightly it is woven. A coarse/rough canvas can be loosely woven so it could be lighter weight than a fine canvas that is tightly woven. But usually, a thick thread makes a heavy canvas and a thin thread makes a light canvas.

7、Stretched across bars or mounted on a panel

----Depending on their painting style, some artists like the bounce of a canvas stretched across bars, others prefer the lack of movement of canvas glued to a panel (also called a board). The rigid support can be made of solid wood, plywood, MDF, heavy card, thin stiff plasticised card, or Gatorboard (plastic impregnated foam board). The canvas can be cut off shear with the edge of the support or it can be wrapped around to the back and glued down. Canvas panels are sheets of compressed card onto which universally primed cotton canvas has been glued. These are ideal for quick sketches, but can also be easily framed as finished paintings.

8、Priming

----The type of ground affects many things about the painting. The amount of tooth affects how well the paint adheres and how much brush-drag you feel as you paint. The amount of absorbency affects the glossiness and brightness of oil colour as the oil is absorbed by the ground and if pigment is also sucked in, the colour will be diminished. After you have sized the canvas you can apply one or more coats of a ground, the surface you will apply paint to that gives the right amount of tooth, also called providing a ‘key’ for the paint to stick to, to create a good barrier against oil paint penetration, and then to make the additional coats as smooth or textured as you wish. For oil painting it is especially important that the oil never reaches the substrate as it will rot the canvas, paper or wood.

9、Clear primer

----Some artists require a clear primer because they wish to use the colour and texture of the canvas as an integral part of the painting. If you like the colour of the canvas and don’t want a white ground you can prime the canvas with a fluid acrylic medium like Matt Medium or a ‘clear acrylic gesso’ to soak into the fibres and fill the weave holes. It usually takes a few coats.

10、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.

11、Tacks

----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.

12、Tooth

----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.

13、Wedges

----Wedges are supplied with ready made canvases and stretcher bars and provide a way of making your canvas even more tightly stretched. Simply insert the wedges into the corners of the frame of your stretched canvas and gently tap in with a hammer. The wedges will push the stretcher bars outwards and keep them in place. If the same amount of pressure is put on each wedge then the canvas will remain square. By pushing the bars outwards you will be tightening the tension of the canvas stretched on the other side of the frame.

14、Whiting

----Calcium carbonate or calcium sulfate - also called chalk, marble dust, calcite and gypsum depending on its source, use, particle size (which affects both the texture (gritty or silky smooth) and the absorbency) and the purity level.

15、Colouring Canvas

----JSRS's collection of coloring canvases offers a fun and relaxing way to create beautiful works of art. Each canvas is pre-printed with intricate designs, ranging from nature scenes to abstract patterns, waiting to be brought to life with color. Perfect for artists of all ages and skill levels, these coloring canvases are a great way to unwind and express your creativity. And once completed, they make a beautiful addition to any home or office.