Canvas is made of all widths and qualities. For sketching use single prime of a pale greyish hue, as the glare of the white canvas out of doors is very disturbing to the eye. It is better for the canvas to be smooth in surface, and not to show its texture through the work, yet it should not be so smooth that the paint does not "bite" easily. Like paper, a rough-surface canvas marks the work to a certain extent, and makes the pupil think his work is better than it is. The texture should be given by the work.* Paper for oil-painting can also be bought, and is very useful for sketches and studies made for a purpose to which no permanent value is attached. The form of tablet for oil-painting called "Academy board" is seldom made of a larger size than "Royal" (22 in. by 19 in.), and is extremely convenient to carry for small paintings. It is pleasant to work upon, but is only suitable for the slightest sketches, and the colour should be used without varnishes, maguilp, or other mediums, otherwise cracks invariably occur in the sketch that after a time go right through the priming of the board.,,[1887 p.47 adds *"The canvas should not be too fresh and moist, for if it is not dry when first used, the colour put on with varnish or rapidly drying medium will dry sooner than the "prime" on the canvas below and cause it to crack at the brush marks."] , ,[1887 p.48 adds final paragraph: "Canvas mounted on millboard is also made and is very convenient for sketching purposes. Two of these boards put face to face, but kept from touching by a light frame of wood, protect one another and can be easily carried.",,[1903 pp.45-46: keeps the information above, with these additions ,-Academy board dimensions are given as "22 inches by 17 inches",,[45]"Many materials are used as a prime for canvas, some of doubtful durability, particularly when thick; but it matters little what they are when thin, as in single prime, as the oil-paint laid on is generally sufficient to absorb the priming by its superior body. Some artists cover the back of the canvas with common white paint to protect it from the influence of damp, and this is not a bad thing to do when painting out of doors in very damp weather. It is better to have the canvas fairly fine to give a smooth surface..[as in 1883]",,[46]"Canvas mounted on millboard is also made; it is more expensive but very reliable. [continues as in 1883]",