While lines are essential to the task of delineating contours and shapes, certain visual qualities of surface and volume cannot be fully described by line alone. Even when we vary the weight of a line to imply a shift in the direction of a surface or an overlapping of forms, the effect is subtle. In order to accentuate shape and model the surfaces of forms, we rely on the rendering of tonal values. Through the interplay of tonal values we are able to convey a vivid sense of light, mass, and space. And through a combination of lines and tonal values, we create the tactile sensation and appearance we call texture.
Vision results from the stimulation of nerve cells in the retina of the eye, signaling patterns of light intensity and color. Our visual system processes these patterns of light and dark and extracts specific features of our environment—edges, contours, size, movement, and color. This assessment gives rise to our perception of separate objects in space.
The light and dark patterns we see emanate from the interaction of light with the surfaces of objects around us. The reflection of radiant energy from illuminated surfaces creates areas of light, while comparatively darker areas occur where there is an absence of light, either because surfaces are turned away from a light source or an opaque body intercepts the rays from the light source.
Just as seeing patterns of light and dark is essential to our perception of objects, the representation of tonal values in a drawing is necessary to depict the lightness or darkness of objects, describe the effect of light on their forms, and clarify their arrangement in space. Before proceeding on to creating and using tonal values to model form and convey the presence of light, it is necessary to understand the relationship between color and value.
Color is a phenomenon of light and visual perception that may be described in terms of an individual’s perception of hue, saturation, and lightness for objects, and hue, intensity, and brightness for light sources. We refer to the relative lightness or brightness of a color as value. Of the properties of color, value is the most critical in seeing and drawing.
Every color has a tonal value, but it is often difficult to discern. If we squint at an object or scene, however, our perception of hues diminishes and patterns of light and dark values begin to emerge. Seeing color values in this way and being able to translate them into equivalent tonal values are essential tasks in drawing with the traditional media of pencil and pen.
Using the traditional media of pencil and pen-and-ink to make dark marks on a light surface, there are several basic techniques for creating tonal values.
These shading techniques all require a gradual building up or layering of strokes or dots. The visual effect of each technique varies according to the nature of the stroke, the medium, and the texture of the drawing surface. Regardless of the shading technique we use, we must be fully aware of the tonal value being achieved.
Since tonal value is expressed primarily through the relative proportion of light to dark areas on the drawing surface, the most important characteristic of these techniques is the spacing and density of the strokes or dots. Secondary characteristics include the visual texture, grain, and direction of the strokes. When rendering the darkest values, we should be careful not to lose the white of the paper. Totally obscuring the presence of the paper surface with an opaque technique can cause a drawing to lose depth and vitality.
Hatching consists of a series of more or less parallel lines. The strokes may be long or short, mechanically ruled or drawn freehand, and executed with either a pen or a pencil on smooth or rough paper. When spaced closely, the lines lose their individuality and merge to form a tonal value. Therefore, we rely primarily on the spacing and density of lines to control the lightness or darkness of a value. While thickening the linear strokes can deepen the darkest values, using too thick of a line can result in an unintentional coarseness and heaviness of texture.
To produce a range of values with a pencil, we can vary the grade of lead as well as the pressure with which we draw. Be careful not to use too dense a grade of lead or press so hard that the pencil point embosses the drawing surface.
Unlike a pencil line, the tonal value of an ink line remains constant. We can only control the spacing and density of the hatching. When using a pen with a flexible nib, however, we can alter the pressure to subtly alter the thickness of the stroke.
The most flexible freehand technique for hatching utilizes relatively short, rapid, diagonal strokes. To define a precise edge, fix the beginning of each stroke with slight pressure. Feather the ends of the strokes to depict curved surfaces, a texture gradient, or subtleties of light and shade. When extending a tonal value over a large area, avoid the effect of banding by softening the edges and overlapping each set of strokes in a random manner.
By applying additional layers of diagonal strokes at only slightly different angles to the preceding sets, we can build up the density and therefore the tonal value of an area. Maintaining the diagonal direction of the strokes in this manner avoids confusion with the underlying drawing and unifies the various tonal areas of a drawing composition.
The direction of hatching can also follow the contours of a form and emphasize the orientation of its surfaces. Remember that direction alone, however, has no impact on tonal value. With texture and contour, the series of lines can also convey material characteristics, such as the grain of wood, the marbling of stone, or the weave of fabric.
Crosshatching utilizes two or more series of parallel lines to create tonal values. As with hatching, the strokes may be be long or short, mechanically ruled or drawn freehand, and executed with either a pen or a pencil on smooth or rough paper.
The simplest crosshatching consists of two perpendicular sets of parallel lines. While the resulting weave may be appropriate for describing certain textures and materials, the pattern can also produce a stiff, sterile, and mechanical feeling, especially when the lines are ruled and widely spaced.
Using three or more sets or layers of hatching provides more flexibility in generating a greater range of tonal values and surface textures. The multidirectional nature of the hatching also makes it easier to describe the orientation and curvature of surfaces.
In practice, we often combine hatching and crosshatching into a single technique. While simple hatching creates the lighter range of values in a drawing, crosshatching renders the darker range.
Scribbling is a shading technique that involves drawing a network of random, multidirectional lines. The freehand nature of scribbling gives us great flexibility in describing tonal values and textures. We can vary the shape, density, and direction of the strokes to achieve a wide range of tonal values, textures, and visual expression.
The strokes may be broken or continuous, relatively straight or curvilinear, jagged or softly undulating. By interweaving the strokes, we create a more cohesive structure of tonal value. By maintaining a dominant direction, we produce a grain that unifies the various areas and shades of value.
As with hatching, we must pay attention to both the scale and density of the strokes and be aware of the qualities of surface texture, pattern, and material they convey.
Stippling is a technique for shading by means of very fine dots. The best results occur when using a fine-tipped ink pen on a smooth drawing surface.
Applying stippling is a slow and time-consuming procedure that requires the utmost patience and care in controlling the size and spacing of the dots. Rely on density to control tonal value. Resist the temptation to deepen a value by enlarging the dots. If the scale of the dots is too large for the toned area, too coarse a texture will result.
We use stippling to establish tonal values in pure-tone drawings—drawings that rely on value alone to define edges and contours. We apply stippling over faintly drawn shapes of the areas to be toned. We first cover all shaded areas with an even spacing of dots to create the lightest value. Then we establish the next value step with additional stippling. We continue to add stippling in a methodical manner until the darkest tonal values are established.
Since there are no objective lines to describe contour and shape in a pure-tone drawing, we must rely on a series of dots to profile spatial edges and define the contours of forms. We use tightly spaced dots to define sharp, distinct edges, and a looser spacing of dots to imply softer, more rounded contours.
White represents the lightest possible value and black the darkest. In between exists an intermediate range of grays. A familiar form of this range is represented by a value or gray scale having ten equal gradations from white to black.
As we begin to see value relationships, we must develop the ability to create corresponding tones using a variety of media and techniques. To this end, producing both a stepped series and a graduated scale of tonal values is beneficial and rewarding. Explore all of the shading techniques described on the preceding pages. Also investigate the possibility of executing a gray scale on a tinted or colored surface, using a black pencil to define values darker than the tone of the surface and a white pencil to establish the lighter values.
After each attempt, carefully evaluate the tonal order from a distance. Check to see if there are any breaks in value and if an even progression of values exists from white to black. With disciplined practice, we should be able to develop the control necessary to replicate any desired tone and maintain the required value contrasts in a drawing.
Modeling refers to the technique of rendering the illusion of volume, solidity, and depth on a two-dimensional surface by means of shading. Shading with tonal values extends a simple drawing of contours into the three-dimensional realm of forms arranged in space.
The modeling of values from light to dark can describe the nature of a surface—whether it is flat or curved, smooth or rough. Areas of light can emerge from a dark background like mounds rising from the earth, while dark areas can appear to recede into the depth of the drawing surface. Gradual transitions from light to dark occur along the surfaces of cylinders, cones, and organic forms, whereas abrupt changes in value pronounce the angular meeting of planes in cubes, pyramids and other prismatic forms.
Since defining edges helps us recognize shape, we look to edges to discover the configuration of the surfaces of a three-dimensional form. We must be careful how we define the nature of the edge or boundary where two shapes of contrasting values meet. The skillful manipulation of tonal edges is critical to defining the nature and solidity of a surface or object.
Hard edges delineate sharp breaks in form or describe contours that are separated from the background by some intervening space. We define hard edges with an abrupt and incisive shift in tonal value. Soft edges describe indistinct or vague background shapes, the gently curving surfaces of rounded forms, and areas of low contrast. We create soft edges with a gradual change in tonal value or diffuse tonal contrast.
Use a soft pencil to create a range of tonal values that clarifies the three-dimensional form of this object. Experiment with hatching, crosshatching, and scribbling techniques to create the desired range of tonal values. Repeat this exercise using a fine-tipped black pen and experiment with hatching, cross-hatching, and stippling techniques to create the tonal values.
Repeat the above exercise but this time use a fine-tipped black pen and experiment with hatching, crosshatching, and stippling techniques to create the desired range of tonal values.
Use a soft pencil to create a range of tonal values that converts the two-dimensional circle, triangle, and polygon into a three-dimensional sphere, cone, and cube. Experiment with hatching, crosshatching, and scribbling techniques to create the desired range of tonal values.
While tonal values can imply depth on a flat drawing surface, we turn to light to more vividly describe the three-dimensional qualities of forms and spaces in our environment. Light is the radiant energy that illuminates our world and enables us to see three-dimensional forms in space. We do not actually see light but rather the effects of light. The way light falls on and is reflected from a surface creates areas of light, shade and shadow, giving us perceptual clues about its three-dimensional qualities. Tonal value is the graphic equivalent of shade and shadow and can only indicate light by describing its absence. In rendering the resulting patterns of light and dark shapes, we invest a form with mass and volume and create a sense of spatial depth.
Almost everything we see comprises a combination of one or more relatively simple geometric forms—the cube, the pyramid, the sphere, the cone, and the cylinder. If we understand that light illuminates each of these fundamental solids in a logical and consistent way, we can better render the effects of light on more complicated subjects. When light strikes an object, it creates a light side, a shaded side, and a cast shadow. Within this light-dark pattern, we can recognize the following elements:
In modeling, we tend to consider first the local value of a surface. Local value describes how light or dark the material of a surface is. It is a constant property of the surface and has nothing to do with light. The quality of light that illuminates a surface, however, modifies its local value. For example, naturally light colors can appear darker in shade than those that are normally deeper in value but illuminated by light. In rendering tonal values, we should attempt to communicate this interplay of local value, light, and shade.
It is important to remember that we perceive tonal values relative to their context. The law of simultaneous contrast states that the stimulation of one color or tonal value leads to the sensation of its complement, which is projected instantaneously on a juxtaposed color or value. For example, when two colors of contrasting value are juxtaposed, the lighter color will deepen the darker color while the darker color will lighten the lighter one. In a similar manner, a tonal value superimposed upon a darker tone will appear lighter than the same value set against a lighter tone.
In order to render the effects of light, we must be able to comprehend the nature of the light source, its spatial relationship to the objects it illuminates, as well as the three-dimensional nature of the forms themselves.
The clarity and tonal value of shaded surfaces and cast shadows provide clues to the quality of the light source.
Cast shadows disclose the relative position of objects in space.
The shape and path of a shadow convey both the location of a light source and the direction of its rays.
Shaded surfaces and cast shadows are usually neither opaque nor uniform in value. We should avoid employing large areas of solid dark tones that obliterate detail and disrupt our reading of the form of a surface. Instead, apply shades and shadows as transparent washes that belong to the form and through which we can read the texture and local color of the surface.
Shade becomes shadow along spatial edges or shifts in planes. In order to retain a sense of three-dimensional forms occupying space, we should distinguish between the values of surfaces in shade and those of cast shadows. Shaded surfaces are often lighter in value than shadows, but this value relationship should be confirmed by careful observation.
Areas of shade or shadow are almost never uniform in value. Light reflecting back from nearby surfaces illuminates surfaces in shade or on which shadows are cast. To depict the modifying effects of reflected light, we vary the tonal value of surfaces in shade and those on which shadows are cast. The effects of reflected light, however, should be suggested in a subtle way so as not to obscure the nature of the surface in shade or shadow.
Arrange a still-life composition on a horizontal surface near a window or under a desk lamp so that clear and distinct shadows are cast by the objects. Squint and focus on the shapes and tonal values of the shaded areas and cast shadows. Use a soft pencil and your choice of modeling technique to render the tonal values you observe.
Repeat the above exercise, using a fine-tipped black pen to render the shaded areas and cast shadows.
Arrange another still-life composition by a window or under a desk lamp. This time, instead of rendering the darker tones with a graphite pencil or ink pen, draw the lighter values on black construction paper with a white pencil.
The mapping of light-dark patterns is the easiest way to begin modeling. Mapping involves breaking down all areas of light, shade, and shadow that we see on a subject or in a scene into definite shapes. Decisiveness is necessary. When a shade or shadow seems indistinct, we must impose boundaries anyway. In doing this, we create an organized map of interlocking shapes that serves as a starting point for later refinements.
Mapping requires reducing the many tonal variations that we see into just a few. We begin by sorting the range of tonal values into two groups—light and dark; or three—light, medium, and dark. Within each group, the tonal value can vary to articulate the nature of the surfaces, but the overall mapping of the values should remain clear. Squinting through half-closed eyes makes this task easier. Another method is to view a scene through tinted glass or acetate, which reduces the number of colors and simplifies the values we see.
The pattern of values establishes the underlying structure that holds a modeled drawing together and gives it unity and strength. If the value pattern is fragmented, then the composition will be incoherent, no matter how carefully rendered or technically competent the individual drawing elements may be. Thumbnail sketches are effective devices for studying alternative value patterns and developing a strategy for the range, placement, and proportion of tonal values in a drawing.
Once the overall value pattern is established, we work from light to dark. We can always darken a tonal value, but once a tone has been darkened, it is difficult to reestablish a lighter value. Here are a few additional points to remember in modeled drawing:
The range of tonal values we use in a drawing influences the weight, harmony, and atmosphere of the composition. Sharp contrasts in value vividly define and draw attention to the tonal shapes. A broad range of tonal values, with intermediate values providing a transition from the lightest to the darkest tones, can be rich and visually active. Too broad a range of values, however, can fragment the unity and harmony of a drawing’s composition. Closely related values tend to produce more restful, subtle, and restrained effects.
The relative proportion of light and dark values defines the dominant tonal value or key of a drawing.
When an intermediate tone is the dominant value of a drawing, it can be convenient to draw on a gray or colored surface, which automatically establishes the median tonal value. This surface tint can serve as an effective foil for darker values established with a black pencil and lighter values rendered with a white pencil.
Arrange a still life on a windowsill or under a desk lamp so that a clear pattern of light, shade, and shadow emerges. Using only the white of the paper plus two values—a light and a middle gray—develop a mapping study of the composition.
Find an exterior landscape containing both near and distant elements. Using a viewfinder to establish the limits of your visual field, develop a value pattern that describes the shapes and tonal values you see in the landscape.
Repeat the above exercises, but this time develop each drawing further by layering additional, intermediate tonal values within each value area.
Whenever we use hatching or stippling to create a tonal value, we simultaneously create texture. Likewise, as soon as we begin to describe the nature of a material with lines, we simultaneously create a tonal value. We should always be aware of this relationship between tonal value and texture, whether smooth or rough, hard or soft, polished or dull. In most cases, tonal value is more critical than texture to the representation of light, shade, and the way it models forms in space.
We use the term texture most often to describe the relative smoothness or roughness of a surface. It can also describe the characteristic surface qualities of familiar materials, such as the hewn appearance of stone, the grain of wood, and the weave of a fabric. This is tactile texture that can be felt by touch.
Visual texture is the representation of the structure of a surface as distinct from color or form. It can be either felt or perceived in a drawing. All tactile textures provide visual texture as well. Visual texture, on the other hand, may be illusory or real.
Our senses of sight and touch are closely intertwined. As our eyes read the visual texture of a surface, we often respond to its apparent tactile quality without actually touching it. The visual texture prompts memories of past experiences. We remember what certain materials felt like as we ran our hands across their surfaces. We base these physical reactions on the textural qualities of similar materials we have experienced in the past.
The scale of the strokes or dots we use to create a tonal value, relative to the size of the toned area and the drawing composition, inherently conveys the visual texture of a surface.
Visual texture can also result from the interaction between medium and drawing surface. Drawing on a rough surface breaks up the deposits of ink or graphite. Lightly drawn strokes deposit the medium only on the raised portions of the surface, while increased pressure forces the medium also into the low-lying areas. In effect, the physical texture of the drawing surface bestows a visual grain and texture on the drawing itself.
Another way to impose a textural quality on an area of tonal value is through frottage. Frottage refers to the technique of obtaining textural effects by rubbing graphite or charcoal over paper laid on a granular, pitted, or other roughly textured surface. This method of producing a textured tonal value is especially useful to prevent overworking a dark tonal value, which can cause a drawing to lose its freshness and spontaneity.
Contrast, scale, distance, and light are important modifying factors in our perception of texture and the surfaces they articulate. Whenever representing texture in a drawing, consider the following factors.
Contrast influences how strong or subtle a texture will appear to be. A texture seen against a uniformly smooth background will appear more obvious than when placed in juxtaposition with a similar texture. When seen against a coarser background, the texture will appear to be finer and reduced in scale.
The relative scale of a drawing determines whether we read a texture as blades of grass, a field of grain, or a patchwork quilt of fields. The relative scale of a texture also affects the apparent shape and position of a plane in space. Textures with directional grain can accentuate the length or width of a plane. Coarse textures can make a plane appear closer, reduce its scale, and increase its visual weight. In general, textures tend to visually fill the space they occupy.
All materials have some degree of texture, but the finer the scale of a texture, the smoother it will appear to be. Even coarse textures, when seen from a distance, can appear to be relatively smooth. Only upon closer viewing would the coarseness of a texture become evident.
Light influences our perception of texture and, in turn, is affected by the texture it illuminates. Smooth, shiny surfaces reflect light brilliantly, appear sharply in focus, and attract our attention. Surfaces having a matte texture absorb and diffuse light unevenly and therefore appear less bright than a similarly colored but smoother surfaces. Coarse surfaces, when illuminated with direct lighting, cast distinct shadow patterns of light and dark upon themselves and disclose their textural quality. Diffused lighting de-emphasizes physical texture and can even obscure the three-dimensional structure of a texture.
Select two or more objects having decidedly different textures. Possibilities include a paper bag and a glass bottle, an egg and a spoon or fork on a piece of fabric, or various fruit in a ceramic bowl. Arrange the objects on a window sill or under a desk lamp so that the lighting emphasizes the various textures. Describe the contrasting textures using any of the modeling techniques.
Repeat the above exercise, but this time move in very close to one of the overlapping edges. Focus on this edge and describe the enlarged surface textures where they meet.
Repeat the above exercises several times, experimenting with both pencil and pen-and-ink media, and working on both smooth as well as rough drawing surfaces.
