Comparing The Values Of Planes

Although the values of planes on a form are caused by a logical relation of how much each plane is facing a light source(s), the differences in the values of those planes appear so subtly that it can be very beneficial to utilize thought processes that make comparing the values of planes easier.  Two of those thought processes are described in this post.

 For each form that I have to model I investigate the location of the point on each form that is most facing the light, also known as the high form light.  To identify the location and value of the high form light it is helpful to evaluate the difference in the position of each of the planes on a form as they relate to a center, which is the light source.

I used concentric circles to illustrate the shape of a magnetic field in this diagram because they are simpler to evaluate than the actual shape of a magnetic field.  Although the shape of magnetic fields are not technically shaped in concentric circles, the shape of a magnetic field has the same geometry as concentric circles. 

 A useful analogy in identifying the high form light is to imagine dragging a magnet on top of each form.  If I imagined the light source as projecting a magnetic field outwards from the center of the light, that is strongest at the center of the light, the magnet on a form would be most attracted to the area of the magnetic field that is closest to the center of the light source.  The magnet on the plane that is most facing the light shows where the high form light is located on a form.

The diagram above shows how magnet A is striking the magnetic field closer to the center than magnet C, because magnet A is facing the light source more than magnet C.  One can imagine the directional path that one would drag a magnet across a form in any direction, whether horizontal, vertical or tilted sideways in order to investigate the position of the high form light on a form.

I used the idea of the magnet and the magnetic field to determine which plane was most facing the light source and then could compare how much the other planes on a form darkened in value away from the high form light plane.  This thought process was also very helpful in managing the hierarchy of value for each of the forms that I tried to represent in my drawing.

Simplifying Forms

The forms and transitions on a cast are made up of planes. A plane is a flat surface of any size that faces the light in a specific direction.

An example of three large planes that are lighter or darker based on how much they are facing the light.

 The planes on a cast can be examined down to the point where the planes can be viewed as tiny microscopic planes, known as micro-planes, each facing the light in specific direction.  But this type of evaluation can become so overwhelmingly complex that it can be useful to identify a larger value hierarchy by simplifying the cast into large planes.

A painted study of the planes on a cast.

By simplifying the planes that generally face in the same direction into larger planes one can more easily get a sense of the effect of light over the entire cast.  Because it can be difficult to pin-point which of the many planes on a cast are generally facing in the same direction it is useful to examine the cast by squinting and looking at it slightly out of focus.  By simply evaluating the large value relationships one can more easily determine which planes are grouping together in value because they are facing in a similar direction.  I referred to the study shown above throughout the process of modeling my cast drawing when I was concerned with the large relationships on my drawing.