The basic terms of painting are:

 Support: The physical structure that carries the painting.

This could be a piece of canvas, paper, a wall, wooden board, etc.
 

Ground: The prepared layer onto which the medium is

applied, sometimes called the primer, carried by the support.

Pigment: The coloured particles suspended in the medium

that give a colour its chromatic identity.
 

THE SUPPORT

The material upon which a painting is executed is divided into two parts, namely, the actual surface or ground, and the support which is the foundation, backing, or carrier for this surface. With techniques such as water-colour and acrylic painting the support may also serve as the ground. Commonly used supports include wooden boards or canvas or textile fabrics stretched on wooded frames and paper. Less commonly used supports include metal, glass (for Crystolean painting) , masonry (for fresco painting) and various synthetic polymers.

 Canvas:
The term “canvas” generally applies to a class of closely woven materials of relatively coarse fibre, such as are used for sail tents, awnings, etc. In painting the term canvas generally implies a coated fabric, ready for use. The word canvas is also used colloquially to mean a finished oil painting.

Artist’s canvas is woven from the fibres of flax, hemp, jute and cotton and of these the best material is closely woven pure linen (woven of flax fibres) with the threads of warp and woof equal in weight and strength. Cotton canvas is suitable for smaller canvases of not more than a metre square and must be closely woven, when however it serves its purpose very well.
Canvas should not tear or split when stretched and should not be bleached or treated with chemicals.
 
Wood and composition-board:
Wooden supports generally include hardwood panels, plywood board, laminated boards, composite boards and pressed wood. The scarcity and cost of close-grained hardwoods generally place such woods outside the range of student materials. The most reliable, permanent and inexpensive type of composition or processed board in pressed wood is called hardboard and normally appears under the trade name of “Masonite”.
 
Masonite or hardboard is a brown building board, about 3 mm thick, perfectly smooth on the front surface, and criss-crossed with the marks of a wire screen on the back side. Masonite is commonly known as hardboard. The material contains no binder, but is made by exploding wood fibre under a steam pressure of about 200 kilograms per square centimetre, and pressing the refined pulp with heat. The fibres interlock and form a permanent hard mass evidently bound by the lignins or other ingredients of the wood. During the process the fibres are impregnated with a very small amount of sizing made of paraffin, which adds a waterproof quality to them. The finished boards are quite permanent, moisture-resistant to a high degree and will not warp readily, making hardboard an ideal support for painting.

Other types of composition-board such as laminated pine and “chipboard” tend to be heavy, cumbersome and are subject to moisture absorption, swelling, deterioration and warping. Many students use so-called Superwood, a composite board developed in the 1980’s that resembles hardboard, is more expensive than hardboard, but is actually inferior to hardboard in terms of permanency.
 
A Debate. Canvas vs. Hardboard:
Over the years I have worked on both canvas and board, and have heard endless debates about the advantages and disadvantages of both. Too many of the arguments are based on fashionable trends and it is therefore useful to look at why, and how, canvas came into use, and why, and how, hardboard became a useful replacement for canvas in the mid-twentieth century.
 
The advent of large efficient weaving looms in Venice during the Renaissance meant that large sheets of canvas could be woven easily and cost-effectively. Although this development was initially driven by the ship-building industry (for sails), it quickly became clear that canvas, when stretched over a wooden frame, was an excellent alternative to the traditional hardwood panels that had been universally used by painters throughout Europe.
 
Best quality hardwood panels were heavy, difficult to produce, expensive, liable to long-term cracking and warping, and limited to smaller dimensions unless jointed (a process that also posed numerous limitations).
 
The obvious advantages of canvas were immediately embraced by Northern Italian painters and within a century, with negligible exceptions, canvas had replaced the wooden panel throughout Europe. Canvas was strong and light, easy to manufacture, could be made to large dimensions and could be removed from its stretcher, rolled up and thus transported easily.
 
Within a short period canvas became the common support for all painters, and after more than 500 years it seemed that canvas had become the universal support for oil painting, giving canvas an artistic status that seemed unquestionable.
 
However, in the twentieth century, with the advances of technology and mass-production methods, many new materials appeared on the market, and Masonite, or hardboard, became widely used in the building industry. As an alternative support to canvas, the durability and affordability of hardboard made it highly popular amongst painters. But the humble functionality of hardboard, as opposed to the grand art historical legacy of canvas, left Masonite being branded as a “cheap substitute” for “real canvas”. I have actually seen amateur painters painting on the textured/reverse side of hardboard to give the tactile impression of canvas weave – a kind of poor man’s pseudo-canvas!
 
When asked why canvas is preferable, most painters will say that there’s something about the “give” (i.e. the springiness) of canvas, or the special character of the woven quality, or simply that it “feels” superior to hardboard. I am not convinced that this trampoline or shock-absorber effect genuinely contributes anything significant to the act of painting, and very frequently, especially when you really work a canvas hard for extended periods, the canvas actually stretches, slackens becomes extremely irritating to work on. This is normally when the canvas needs to be removed from its frame and re-stretched onto its frame to tighten it again – in itself an irritating process. The traditional expansion wedges that allow the canvas to be tightened by simply hammering the wedges deeper into the corner joints are notoriously ineffective, especially on larger canvases.
 
Some painters will say that they like “weave” effect of canvas, and yet, for example, will complain bitterly when they’re trying to paint some intricate detail onto a surface that when closely inspected, is actually undulating and knotted range of crevices and bumps. The absurdity of these prejudices are highlighted most clearly by the so-called artist’s canvas boards, canvas stuck onto lightweight boards and sold in most art shops worldwide. Why bother to apply a second support (i.e. canvas) over a first support (i.e. board) when it’s actually the ground that will determine the characteristic absorbency, responsiveness and behaviour of the painting surface?
 
Bearing in mind that canvas evolved as a somewhat less-than-flat substitute for wood, and that 500 years later hardboard managed to combine the best of both supports (i.e. rigidity, flatness and neutrality of surface, affordability, permanency and an excellent weight-to-strength ratio), it seems canvas is too often chosen for reasons of pointless nostalgia.
 
Evidence suggests that properly manufactured hardboard is probably more permanent than canvas. The outdated custom of re-using canvas stretchers was also based on the fact that the accurately manufactured handmade stretchers were expensive and also offered the convenience of being able to remove and roll up completed paintings to facilitate ease of transport in an age when freight transportation in Europe was limited to manual haulage and horse-drawn coaches. Since none of these considerations apply anymore, it seems peculiar to demand the re-usable stretcher without ever intending to re-use such stretchers.
 
In view of the above, and unless there is some genuine requirement for canvas, there is no reason to consider hardboard an inferior support for painting. In my view, a well grounded hardboard support provides a painting surface that combines, and exceeds, the best qualities afforded by the original wooden panels and the artist’s canvas, for a fraction of the cost.
 

Paper:
Paper should here be divided into two categories:

Firstly, the general mass-produced paper and card which is relatively inexpensive and serves as an expedient support for sketches and experimental painting where permanence is not required.

Secondly, and the more pertinent category is related to water-colour techniques. The best permanent paper for water colour is most carefully made from linen rags (a small percentage of cotton is permissible) which are boiled, shredded and beaten to separate the fibres; the material then assumes the form of a smooth, flowing pulp. It is run over a fine screen in a thin layer, dried and pressed. For the most permanent kinds of water-colour and drawing papers no chemicals may be employed, with the exception of a little bleaching agent, the surplus of which is destroyed and neutralised by means which leave a harmless residue in the paper.

The better papers are watermarked or embossed with the manufacturer’s mark, the side upon which this can be read being the right side. Many papers are well-finished one side; the wrong side may contain irregular spots, flaws, and blemishes which do not show up until painted upon, or its grain may not be the same. Other papers may be used on both sides equally well.