I am foxed by the use of dots and stipples to produce shading especially when that involves using a biro which has a very thin point and hence involves a lot of time in the production of an area of shade with small dots—-and feels virtually impossible.
I googled shading using stipples and dots :
“Stippling has traditionally been favoured over hatching in biological and medical illustration, since it is less likely than hatching to interfere visually with the structures being illustrated (the lines used in hatching can be mistaken for actual contours), and also since it allows the artist to vary the density of shading more subtly to depict curved or irregular surfaces.” ref:http://en.wikipedia.org/wiki/Stippling
I have not yet aquired a reference book for drawing but do have Ian Simpson’s “Drawing Seeing and observation” 1992 and found works by the following artists who have used stippling:
La Grille, 1882-1884 Conté crayon – 24.8 x 32.4 cm New York, Solomon R. Guggenheim Museum ref: http://www.thearttribune.com/Georges-Seurat-The-Drawings.html
Vincent VAn Gogh Ink drawing over black chalk ref: http://www.britishmuseum.org/explore/highlights/highlight_objects/pd/v/vincent_van_gogh,_la_crau.aspx
Here Van Gogh uses dots and stippling in the middle distant fields and straight and curved lines in the foreground. This seems to give a greater sense of movement in the foreground and activity but not of any variety in the mid ground. The stippling does not vary in size of “dots ” nor their distance apart as they reced further from the eye.
I have been trying to achieve a depth of tone with stippling and dots but perhaps it cannot lend itself to the intensity of shade found in Seurat’ pictures–perhaps it represents more of a graduation between none shade and shade with little propensity for a graduation through shade itself.