Light on Basic Forms II

Today, we shall continue the investigation of how Andrew Loomis unpacks the principles of light and its effect on forms.  Following the 4 Laws Loomis provides for us, as outlined in the previous posting, he continues with some very useful particulars regarding light and shadow.

The first of these particulars is the phenomena Loomis calls the “illustrator’s hump”, that is the observation of how on a curving surface, the darkest part of the shadow appears closest to the lightest part.

This seems counter intuitive, as per the idea that the furthest point away from the light source must be the darkest point, until one realizes that light also reflects. The darkest part shows at the point of change from light to dark, on account of the fact that a certain degree of the cast light reflects back from the surface which the lit object is laying on. This reflected light, or other ambient light partially illuminates the object.  This phenomena does not occur on the Moon, because the Heavenly Bodies are objects which are actually suspended in space, and there are no planes below them, which could reflect the light back onto the dark side.

A further observation about the ‘illustrator’s hump’ is that the shadow which the object casts begins where the “hump” on the surface begins.  Tracing a light line in the direction which the light is falling will show you where to put the edge of the shadow which the object casts on the plane it sits upon.  For clarity, please refer to the illustration I have done, just below.

 

illustrator's hump

Further particulars which Loomis outlines in this section are some rules on how to think of the principles of light and shadow in regards to the angle the subject sits at, relative to the light source.  If one thinks of angles, rather than the puzzles of how to render light on a surface, many potentially confusing traps can be avoided.  He provides us with the following principles.

  1. An object between the viewer and the light source is in full shadow.
  2. If the light is behind the viewer, the lit object is cast in full light, as in the effects of a flash bulb.
  3. If the lit object is placed at right angles to the viewer’s position, as well as to the light source, the object seems to be half in light and half in darkness.
  4. If the lit object is placed in a quarter-turned position, the resulting effect is either 3/4 light and 1/4 dark, or vice-versa.

Loomis further indicates that quarter turned positions present a more satisfactory effect, as either light or dark then dominates the subject matter.  This appears more appealing to the viewer than an equal division of light and dark.

Finally,  there is concession which Loomis gives to certain cases where an even dispersal of light on a subject is appropriate, for instance he indicates that full-frontal light is good for posters and poster effects, such as in the work of Norman Rockwell.

Thanks again for reading, next week we will cover the 2 main types of light, cast shadows and how to represent shadows properly in perspective.

Cheers.

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