1. The Perceptual Grid
by Brian Curtis
© 2002, The McGraw-Hill Companies

2. A PowerPoint lecture series to accompany DRAWING FROM OBSERVATION

3. Vertical / Horizontal Grid
Human beings naturally possess an innate predisposition toward the vertical and horizontal.
The innate predisposition toward the vertical and the horizontal provides us with a perceptual baseline against which to compare and contrast our visual experiences.
It is so deeply rooted in our consciousness that references to these orientations are used to represent dignity, balance, stability, truth, strength, well being, and peace. We are encouraged to “grow up straight and strong,” to be “level headed” in our decisions, to be “square” in our dealings with others, and to “stand up” for what is important to us.

4. The Egyptian symbol for life (ankh) and the almond-shaped symbol of the universal mother (Vesica Piscis) are organized in accordance with the x/y grid that serves as the perceptual baseline of our visual experience.

5. The Christian cross and the interlocking triangles forming a six-pointed star (star of David) are organized in accordance with the x/y grid that serves as the perceptual baseline of our visual experience.

6. The Greek’s five pointed Pythagorean Star and the astronomical (also the astrological) symbol for our planet Earth are organized in accordance with the x/y grid that serves as the perceptual baseline of our visual experience.

7. Piet Mondrian’s paintings were strongly influenced by his study of ancient wisdom and its sacred symbols. Because x/y axis relationships dominate his compositions, the hand-held straight-edge that you will use to establish the x/y perceptual grid will be referred to as the Mondrian Tool.

8. Don’t even think about moving !
Stand still when drawing from observation. If the observer moves, the relative positions of the objects in the visual field change. Even shifting your weight from one leg to the other can make a surprising difference in how the objects appear in relation to one another.

9. An apparent change in the position of an object, caused by a change in observational position that provides a new line of sight.
parallax

10. The X/Y Axis
Because we are so adept at recognizing the vertical and the horizontal in the world around, we can benefit by translating this ability into a technique for checking the placement, size, shape, and proportion of the objects in our gesture drawings.

11. The Mondrian tool can be any straight edged tool that is held at arm’s length in a position we intuitively "feel" is either vertical or horizontal. We can increase our responsiveness to perceptual information by physically superimposing our sense of verticality and horizontality onto our field of vision. To safeguard the immediacy of your perceptions you need to align your Mondrian tool to the vertical or horizontal axis in front of a blank wall or neutral space. If you align your straight edge while it is in front of an object, you run a considerable risk that your understanding of that object will substitute preconceptions of orientations for what otherwise is a dependable and direct intuitive sense of x/y orientation.
Once you have intuitively aligned your straight-edge with either the x or y axis, you can move it in front of any two elements that you intend to compare (Fig.5.6b). Remember to start fresh every time you use your Mondrian tool. Starting fresh engages your intuition and helps you avoid being influenced by what your rational mind “knows.”
The “Mondrian” Tool

12. Any easily held straight edged tool - pencil, ruler, stick, etc
Any easily held straight edged tool - pencil, ruler, stick, etc. - that is at least four inches in length can be used as a Mondrian tool. To function properly, it must be held so that the straight edge is perpendicular to your line of sight. Establish your x/y orientations while looking straight out in front of you (toward what would normally be the horizon) before carefully moving it to check alignments in either your visual field or your drawing.

13. The Mondrian tool is intended to be used as a supplement to intuitive gesture. It should be applied only after you have made extensive sketchy references to the “where” and the “how big” of each and every element that you intend to draw. The Mondrian tool can then be called upon to generate countless vertical and horizontal comparisons between any two prominent points within your visual field. These perceptual grid comparisons can then be transformed into a delicate web of corresponding vertical and horizontal lines and applied to the surface of your gesture drawing. Horizontal and vertical “Mondrian” lines can be used to align distinctive features of objects with those of other objects. It is particularly effective to compare the vertical and horizontal relationship of features that are far apart from one another.
“Mondrian Lines” encourage us to jump quickly from the far left to the far right and to look for the relationship of things in the top of the gesture drawing to those at the bottom. Using a Mondrian tool to superimpose an x/y perceptual grid on the objects in our visual field allows us to identify when salient features of an object are vertically or horizontally aligned with salient features of other objects.
Mondrian Lines

14. MORE MONDRIAN!
Superimposing an extensive, delicate web of x/y perceptual grid lines to an intuitive gesture drawing provides an effective mechanism for evaluating the accuracy of your initial estimates in determining the “where” and the “how big” of the elements in your drawing.

16. Mondrian grid lines should be applied to your drawing only after you have estimated the size and placement of each of the objects. Gesture first, Mondrian second. Repeat as often as necessary. Whenever you encounter discrepancies between your gesture drawing and the x/y relationships you find with the Mondrian tool, make all needed adjustments.

17. Making sure that the x/y relationships in your gesture drawing conform with those in your visual field substantially increases the accuracy in the placement, the size, the proportion, the shape, and even the approximate linear perspective of the objects that you are observing. When the Mondrian relationships in your drawing match those in your visual field, your drawing is alive and well

18. This extended gesture drawing was worked on for approximately two to three hours. The student who did this drawing had little or no clear understanding of the spatial mechanisms underlying linear perspective. Nonetheless the student was able to resolve complex spatial relationships by relying upon intuitive gesture, intensive use of the Mondrian tool, and a generous application of a delicate grid of Mondrian lines.

19. There can never be too many Mondrian lines
There can never be too many Mondrian lines. The linear grid that develops on the drawing surface represents your natural sensitivity to the x/y axes. When you combine a gesture drawing (a simultaneous overview of complex relationships in space) with the x/y perceptual grid you have the necessary tools to create complex spatial relationships on the drawing surface. An extended gesture (intuitive gesture plus Mondrian gesture) needn’t be detailed or “finished” to be successful. It need only be an energetic overview of the relation of forms in space and remain fluid, flexible, and responsive to continual adjustment.
Not only do Mondrian lines contribute to greater visual richness in mark making, they also contribute a meaningful graphic representation of a sophisticated search for perceptual clarity.

20. An extended gesture drawing has multiple levels of content
An extended gesture drawing has multiple levels of content. It conveys your struggle to locate the objects in relation to the perceptual grid, as well as revealing the visual character of the objects themselves. Underlying it all is your sensitivity to the touch of the drawing tool to the paper.

21. Superimposing an extensive, delicate web of x/y perceptual grid lines to an intuitive gesture drawing provides an effective mechanism for evaluating the accuracy of your initial estimates in determining the “where” and the “how big” of the elements in your drawing.

22. Convincing illusions of objects in space can be very closely approximated with a rigorous application of intuitive gesture and the perceptual grid.

23. Alberti’s “Veil”
In 1435, in his treatise on painting (De Pittura), Leon Battista Alberti discusses the construction of a simple tool for the direct transcription of objects as they appear to the eye. He suggested weaving thread in a network of parallel squares on a wooden frame. By viewing objects through this “intersection” from a fixed viewing position, the arrangement of forms in space could be duplicated on a drawing surface that has been divided into similar squares. Leonardo da Vinci, Raphael, and Albrecht Durer, along with countless other artists, designed similar drawing devices to study nature. Leonardo is on record, though, as having been very critical of those who could not draw without this type of mechanical assistance. Today, photography and digital imaging have generally replaced Alberti’s "veil” as the artists’ preferred tools for gathering visual information. Meanwhile, the debate as to whether mechanical imitation encourages aesthetic and intellectual barrenness continues unabated.

24. Alberti’s proposed mechanical drawing device is generally too impractical for most artists, but his description remains an effective model for visualizing how the picture plane functions.
picture plane #1

25. The images above depict the imaginary window through which the observer is viewing several objects from a fixed viewing position. In these illustrations the white dots represent those points where the line of sight intersects the imaginary picture plane. As the line of sight shifts further back in space, the progressive depth appears as movement up the picture plane.

26. Not only is the picture plane an imaginary transparent “window” that the observer looks through to observe objects in space, it is also to be understood as the actual flat surface of the drawing itself.
picture plane #2

27. This concludes the lecture
The Perceptual Grid