Perspective - Part 1
By Margaret Saul
Originally appeared in The Botanical Artist – Volume 14, Issue 1
“Learn how to draw, and let the magic begin!" Perhaps this message could stir potential botanical art students to action. So how do you go about designing a program that sees your drawing classes meet the expectations of beginners especially when - assured that with careful guidance and plenty of practice – anyone can learn to draw? How do you present classes about “perspective” that are not too technical or send students into a spin?
One effective approach is to progress in stages: explain the general concept of drawing in perspective; show examples of drawings with and without regard to perspective; explain the usual problems encountered and why they occur; provide useful class exercises, and ensure the purpose and outcome of each exercise is explained; include aspects of technical drawing helpful for developing basic drawing skills with practical applications in botanical art.
Teaching perspective is an essential part of learning to draw. It helps to develop observation skills, creating awareness of how various shapes change in relation to their height and direction from the viewer; and it increases the perception of the third dimension, creating more life-like drawings, and botanical paintings that appear to “pop out from the page.”
Perspective drawing terms
Plane – flat surface (e.g., a sketch book page)
Picture Plane – the imaginary plane from where measurements are taken
Eyelevel – the horizon (the greatest distortion of elements in your subject can occur at this point)
Vanishing points – points at which various lines (those related to the “planes” of an object extended away from the picture plane) appear to converge on the horizon. This may be at one central point directly in front of the viewer or as split vanishing points either side of the viewer.
Elements of perspective
Lines or edges appearing to converge to one or two vanishing points; a constant eye level; a sense of progression interpreted by the sequence of overlapping of various elements; elements whose natural size is diminished or whose shape is distorted due to their distance or angle to/from the picture plane; and finally, atmospheric affects where the degree of tone in the drawing (tonal contrast) is manipulated by the artist to create either a sense of prominence or recession.
The picture plane as teaching aid
Tools: A sheet of clear plastic about 8x10”, a fine point dry erase pen, and florist oasis. The plastic is used as a visible picture plane to demonstrate how to visualize a three-dimensional image as a flat shape or series of inter-related flat shapes and to relate this flat surface to the drawing page. A similar teaching aid was used by Leonardo da Vinci when teaching his students.
Exercise 1 – The concept of the picture plane
The student positions a plastic sheet (the “picture plane”) at a comfortable viewing height and at arm’s length, then places the object directly behind it. Students should sit comfortably and not stoop. Closing one eye, students use their dry erase pen to roughly trace the object onto the picture plane. Point out how this tracing action helps them to understand the shift in mind set that sees a three-dimensional object transformed into a two-dimensional contour drawing. Squinting may be help to reduce the perception of three-dimensionality. Then explain how this plastic sheet aids in creating a mental connection in understanding why the picture plane is similar to a “flat” sketchbook page.
Exercise 2 – Perspective alters the appearance of natural dimensions
Use a stiff leaf such as a southern magnolia or rhododendron leaf. Step 1: Students position their leaf behind the picture plane with its petiole pointing upwards and the lamina flat up against the picture plane. Trace the shape onto the picture plane so the outline of the leaf illustrates its natural dimensions (do not erase). Step 2: Position the same leaf with the base of the petiole to one side of the first outline, in line with that on the traced image but so its mid rib is receding from the picture plane at right angles. Quickly trace the image as viewed on the picture plane. With the two images side by side it is easy to see the degree of distortion in the second leaf that is tilted away from the picture plane. Here the length of the leaf appears shortened (“foreshortened”) due to perspective. Step 3: Place the plastic picture plane, with its ink line images, under a sheet of drawing paper and trace lightly. Step 4: Erase the previously drawn images from the picture plane. Position the same leaf horizontally but close to eyelevel and tilt the lamina at right angles to the picture plane so only one of its side margins touches the picture plane. In this view it is the width of the leaf that is grossly foreshortened. This is why botanists prefer illustrations as if pressed on an herbarium sheet showing most leaves drawn in 2-D, without foreshortening.
Exercise 3 – Measuring perspective dimensions
Teachers may prefer that students do not rely on this method too early in the process of learning to draw. Use a clear plastic ruler for basic measurements or free-arm dividers that are easier than using a ruler when measuring directly on the picture plane. Step 1: Using the picture plane demonstrate how and why all measurements must be taken ON the picture plane. Step 2: Explain how measurements taken on the picture plane record the foreshortened measurements that provide the illusion of depth in the drawing and why a measurement taken through a picture plane will not represent the true dimensions.