Its relative cost effectiveness, medium-toothed texture and natural feel give the cloth appeal for a variety of artistic techniques. The warp and woof fibres need to be tightly laced at right angles however, to hinder primer undercoats from seeping through to the back-end of the cloth. Although differently weighted Cotton Duck is used in a wide variety of different applications, only the more expensive and heavier cloth is suitable for painting; 10oz cloth is sufficiently heavy and with a thickness of approximately 0.68mm, gives the material durability and strength for palette knife work. In its natural state, the cloth has an off-cream colour in appearance, and at Winsen's Canvases is available in 3 meter wide rolls. A stretched canvas can therefore be as large as 2.7 meters by 5 meters+. The cloth is washed and scoured, removing any latent residue as a consequence of the milling process.
The primer is essential to obtain a support that is flexible, protecting the underlying fabric from canvas deterioration and allowing the correct absorption of oil or acrylic paints - as a default, we double-prime the cloth with a pure acrylic flexible polymer that has low VOC’s (volatile organic compound) and is lead free. Extenders within the primer are Calcium Carbonate and Titanium Dioxide (whitener). Because acrylic polymer does not contain the acids which tend to deterioate cotton and linen fibers, the use of size is unnecessary. The absence of glue size and the hydroscopic character of acrylic polymer produces a stable ground and extra coatings can be given such that the final finish tend toward a smoother feel and more lustrous appearance. Gesso and binder medium can also be used in combination with an acrylic primer - gesso tends to add more texture or tooth to the final finish while limiting the absorption of oil and acrylic paints.
Being a natural fibre, the cloth is hydroscopic in nature and can relax depending on environmental conditions; when dampened, the individual threads become thicker and shorter causing the intervening openings to close and hence an overall tightening on the cloth. During dry conditions, the reverse process causes the cloth to slacken or ‘relax’, an expansion stretcher frame is therefore needed with keyed wedges in the corner and cross-bar struts. These can be gently tapped in, effectively bringing the cloth back to a taut state.
In summary, Cotton Duck’s versatility has found favour for many different styles of artistic impression. Its toothed surface finish grabs brush paint easily, giving long-lasting adhesion to priming and subsequent oil or acrylic paints. References:  The Artist’s Handbook of Materials and Techniques. Fifth edition. Ralph Meyer  The Artist’s Pocket Guidebook. Jim Cobb and Kirk Miller  The Painters Handbook. Mark David Gottsegen.  The Materials of the Artist and their use in Painting. Max Doerner.