Light on Basic Forms

The third main section of Successful Drawing deals with the techniques artists use when rendering  light and shadow on the basic forms. (Please see my previous postings regarding how illustrators simplify the many organic shapes in nature, down into a handful of basic geometric shapes.)  Here again, Loomis articulates a principle of representational art which is easily overlooked when an artist is attempting to represent a subject.  He states that light and shadow are the phenomena which delineate what we call form.  Furthermore, he reminds the reader that the entirety of the visible world is light falling on form.  What our eyes perceive as a shape, or colour is actually the effect of light striking a 3-dimensional mass.  Comic artists who work in line are sometimes forgetful of this truth. Although line is a fine method of describing light on form, too often does the line-based illustrator become fixated on the particularites of design when drawing, rather than acknowledging that perceived form is actually a phenomena of light.

Next, Loomis indicates that Nature is too complex for any artist to memorize or even attempt to fully translate into a piece of representational art.  He reaffirms the aforementioned concept of relying on a system in order to understand the infinite variables found in Nature.  Frankly stated, Loomis indicates that one must simplify light and form.

To warm his readers up to the concept of form being a phenomena of light, Andrew Loomis considers the heavenly bodies in the solar system, drawing attention to the general shape of such bodies -the sphere.  When one imagines the full moon on a very clear night, generally the shape pictured in the mind’s eye is a white circle.  Yet, if you really look at the moon, you will see that there is actually a gradation of bright white to light grey on the mass.   The section which appears brightest, is that area of the Moon’s surface which is at right-angles to the Sun.    As a short hand rule, one can consider the highlight as the shortest distance between the lit surface and the light source.  

This highlight curves around the face of the Moon, and diminishes in value to least amount of light, at a point 180 degrees opposite the highlight.  The shadow begins to form on the sphere where the light is at a tangent to the surface.  This phenomena of shadow always begins at the halfway point between the surface nearest to the light and the opposite face, which is furthest from the source.

Andrew Loomis provides for his readers a Set of Laws which can be pulled out as summative facts regarding Light on Form.

  1.  LIGHT TRAVELS IN A STRAIGHT LINE.  This Law shows why a single light source is not able to reach more than halfway around any round form.
  2. SURFACES ARE LIT AT ANGLES RELATIVE TO LIGHT.  This Law is meant to awaken the artist to the phenomena that any surface which is represented, is lighted according to the angle of its surface in relation to the direction of the light source.  When one begins to think in these terms, determining value is made accessible.
  3. RIGHT ANGLES ARE BRIGHTEST.  Planes which are fully flat appear brightest, and on curving shapes, that piece of surface area which is at 90 degrees to the light source likewise appears brightest.
  4. GRADATION = CURVING.  This law is easily forgotten when inventing value representation.  The curving plane is rendered with gradations of light to dark.  The flat plane is not.  The flat plane is lighted evenly, relative to its degree facing the light source.

This fourth Law is really the father of the others, and it is the secret of lighting.  To restate, flat planes are also flat in tone or value.  They appear even; even in colour and lacking variance.  Rounded masses on the other hand are described with modelling of value and gradation of tone.

Thank you for reading this week’s blog.  Next posting will go into a further consideration of the effects in value related to an object’s relative degree facing the light source.  See you in 7.

One thought on “Light on Basic Forms

  1. Thanks Jess, that is a very logical explanation that I will pass on to my classes. One of my standard statements is ‘ light and shadow create form’ .I try to stress it; this will help the more serious painters unravel this complex idea.
    Strange coincidence, Lal’s text last night was about the way the eclipse made the moon appear more spherical and therefore more real … and quoting my refrain” light and shadow…. “Haha!!
    Love Mum
    Ps did you guys see it? We did but it wasn’t red just a dark rusty colour, but very beautiful.

    Sent from my iPhone



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