Optical Illusions – Tonal Contrast and the ‘Checker Shadow’ illusion.
Last week we discussed whether we really needed to know any of the ‘rules’ of drawing, or whether we could achieve results by just ‘drawing what we see’. I would argue that the ‘rules’ of drawing are there to aid us, but we should not necessarily feel bound by them. But that’s just my opinion. From our discussion the question was raised, “how well are we able to see what is in front of us”. While it’s a topic that deserves much more attention, for now I thought we should consider the “Checker Shadow Illusion“.
My reason for including this in todays session is that it is useful to understand that the things we see are effected by what is around them. This applies to colour as well as tonal values…
Tone is created by light falling on an object and describes how light or dark the object looks. It gives an object form and can help create an illusion of depth. The darker areas give the illusion of shadow while the lightest areas represent the highlights.
You can organise your tonal values something like this:
If you are drawing with a graphite pencil, it can be difficult to get really dark tones. Using the softest pencil possible, with a sharp point, will help.
There are a variety of techniques that we can use to create tones when we are drawing. These include:
Blended Shading. Graphite drawn onto paper and smudged with your finger or a tissue
Circulism. Drawing in a circular motion, overlapping to build up darker tones.
Blended Circulism. Mixture of techniques above. Graphite drawn onto paper, then smudged with a circular motion using a blending stump.
Hatching. Drawing straight, parallel lines.
Crosshatching. Drawing straight lines across each other, first in one direction, then another. These can be loose or tighter together.
Contour Hatching. Drawing lines which follow the contour of the objects form.
Stippling. Using dots to build up tone. When drawing with a graphite pencil, darker areas are created by adding more dots which are closer together.