aids to drawing

It's fair to say that photographs have become the principal aid to drawing used by artists today. A credible style of contemporary painting (photorealism) consists of the meticulous copying of photographic documents, and this style has challenged other "realist" painters with a distinct visual world and color sense. Artists also trace photographs onto the support as the foundation drawing for paintings done in a less realistic style. Even a nonrepresentational artist's "visual culture" is enriched by the sense of light, contrast, color, saturation, focus, perspective, depth of field, optical curvature, movement, blur, flare and halo that have been ingrained in us all through daily exposure to the products of optics, photography, video, film and computer design.

My aim is to fit some of these themes into the methods artists use as aids to drawing. I describe four basic activities. Most important is the use of photographic materials for foundation drawings. These materials can also be manipulated to model a painting effect that is not imagined in photorealist terms. Photographic media can be used in the experimental or playful search for new visual effects or visual compositions in painting, by image collage or image editing. Finally, the artist can use photographic media to clarify or analyze a specific visual problem.

not a new idea

The idea of using optical aids in drawing or painting is quite old. The traditional account is that the Florentine architect Filippo Brunelleschi (1377-1446) worked out the principles of linear perspective by meticulously painting the view from a room on a windowpane. And several woodcuts from the 15th century show artists studying the perspective of objects by viewing them through grids of wire or scribed glass; the outlines of objects were copied onto paper or canvas, square by square, as the foundation drawing for a finished work.

Traditional Tools. The first practical optical device was the camera obscura or "dark room," mentioned as early as the Roman era (in a treatise on painting by Pliny, 50 AD), but especially popular from the 16th to early 19th centuries.

The original camera obscura was literally a small room with a rotatable metal mirror on the roof. The mirror reflected the surrounding landscape downward through a small hole in the roof, where it could be viewed on a flat white table underneath. By the 17th century these rooms had been reduced to a portable wooden pyramid (about the size of a modern washing machine), with a mirror at the apex and a opening in one side that allowed an artist to trace the projected image on a sheet of paper inside.

These cameras obscura had two important effects on artistic practice: they provided a tool for tracing or copying complex images, and they created a model of visual fact — in the outlines, colors, values and even optical distortions of two dimensional images — that affected artists' expectations of painting and perceptions of reality.

Recent art historical research by Martin Kemp has expanded our appreciation of the linkages and overlapping interests of artists development of linear perspective and scientific studies through a variety of optical, surveying and "image recording"

More recently, the expat British artist David Hockney has marshalled evidence for the use of cameras obscura, curved mirrors and lenses by European artists startin with Dutch painters of the early 15th century. (He suggests many early painters used a convex mirror to reflect a brightly lit image seen through a small window.) Paintings by Jan Vermeer (1632-1675) of Delft were almost certainly created using a camera obscura (probably a large booth, using Dutch lenses rather than mirrors): the highlights in many of these have the peculiarly rounded, disklike appearance that can only be produced by the magnifying effect of an optical lens. More recently, new research on Thomas Eakins has confirmed he extensively relied on tracings of photographic images to compose his paintings.


not a new idea

copying the image

tracing the image

documenting with photographs

creative editing with photographs

representing the world

By the late 18th century, the camera obscura was the size of a small suitcase (illustration at right) and the optics had improved sufficiently so that the device could be used in the field. An adjustable lens focused the image onto a mirror at the back set at a 45° angle, which reflected the image upwards onto a flat sheet of glass, shielded from daylight by a folding screen, where the image was traced onto paper. Use of the camera obscura was also much more out in the open — less secret, and employed in landscape or topographical work.

A different instrument became popular at the beginning of the 19th century — the camera lucida, commonly described as an invention of the English scientist William Hyde Wollaston in 1806 (he patented it as a portable drawing device in 1807). This consisted of a partially silvered prism that reflected or transmitted the images from two different directions; the prism was held by a mechanical arm clamped to the side of a drawing table or drawing board. The artist sat at the table or placed the board in his lap and looked into the prism with one eye (illustration at right). The prism was adjusted so that the transmitted image of the object to be drawn was superimposed over the reflected image of the drawing hand on the paper; this allowed the artist to trace the outline of the image on the paper. Cornelius Varley, the architect brother of John Varley, patented in 1811 a camera lucida that embedded the prism within a small telescope. This presented through a single eyepiece the reflected image of the paper actual size, and the transmitted view the image to be drawn under limited magnification.

These tools were difficult to use in the field, but hardly impractical. John Cotman used a camera lucida for his series of English architectural etchings (actually, a female assistant prepared a basic drawing for him, as he had trouble using the tool himself), and many topographical artists used similar instruments as well. The camera lucida was not used to trace all the outlines in a drawing, but rather to notate quickly the major corners, edges and curves of the important forms (the work of a minute or less), which were then connected together freehand.

The New York critic Susan Sontag commented, "If David Hockney's thesis is correct, it would be a bit like finding out that all the great lovers of history have been using Viagra." Cute, but hardly accurate. Art is the activity of creating compelling imagery as physically valuable objects — not simply performing manually difficult graphical tasks. Artists use what they can as well as they can, including any fruits of contemporary technology available to them. It's their imagination, passion and attentive care — not their tools — that make them great lovers.

David Hockney's visual and documentary evidence for the use of optical aids in western painting from 1430 onwards is reviewed in Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters (Viking Studio, 2001). This includes his correspondence with other art experts, some of whom are converts to his theory.

copying the image

Artists today have abandoned these traditional tools as ineffective and cumbersome. When optical aids are required, they typically photograph the scene with a camera, then use any of the methods described below to transfer this image in the studio. The drawback to this method is that it forces reliance on the photograph for most or all judgments of lighting, value and color: it eliminates direct sensory impressions from the creative process.

The most common remedy is to photograph the scene, but also to make color studies and design sketches on the spot, then combine these notes with the photograph to make the final painting.

a portable camera obscura

making a portrait with
a camera lucida

Full Scale Methods of Copying. Perhaps the most direct approach is to prepare a full size sketch or life drawing, then transfer this cartoon to the support at a 1:1 scale.

A convenient and quick alternative is the "flip" method: I lightly tape the cartoon to the support at the edge opposite my drawing hand, and with my free hand repeatedly flip the drawing over and away from the support, each time marking with a pencil the location of important lines, corners or mass centers. With a little practice this shadowing (it's not really a tracing) can be done quickly and accurately. The trick is to fix your eye steadily on a specific point in the drawing, then flip the cartoon away to mark it with your pencil, then check the location by flipping the drawing over it again.

Neither of these methods should be used to trace the drawing exhaustively. This leads to a copy that looks lifeless and stiff. Instead, mark out the most important landmarks and recreate the drawing freehand on the support. This allows you to correct minor disproportions in the cartoon, and bring everything together with a unified sense of gesture and control.

"Squaring" Methods. Traditional methods that still come in handy involve tracing or "squaring" an opaque image, such as an etching, drawing, finished painting, magazine illustration or photographic print.

The simplest method is tracing the image. Lay a sheet of thin vellum (available at most art stores, and at many stationery stores in the drafting supplies section) over the image to copy and trace it with a pencil. Then transfer this tracing to the drawing or painting surface. To provide a firm support and to keep the tracing from slipping during work, both the drawing paper and the overlay of vellum should be securely taped or stapled to a drawing board. The transfer can be done in one of four ways:

1. The tracing is lifted slightly and the pencil is moved freehand underneath the sheet.

2. The tracing sheet is laid drawing side down on the drawing surface, and rubbed with a burnishing tool over all drawn lines. This transfers a faint impression of the line to the drawing sheet (but reversed left to right).

3. The back side of the tracing sheet is rubbed with a graphite pencil over all the traced lines, then laid drawing up on the drawing sheet. All the drawn lines are traced with a pen or pencil, and the pressure transfers some of the graphite on the back of the sheet onto the drawing surface.

4. A sheet of carbon paper can be placed between the vellum and the drawing surface, and the lines traced the same as in 3.

There are two drawbacks to this method. The major drawback is that the drawing must be copied actual size - you cannot enlarge or reduce the drawing or change its proportions in any way. The second is that the transfer pressure of the tracing pencil tip often leaves depressed lines in the surface of the paper, which can be difficult to cover completely when the paper is painted (the brush does not fill the depression, or the depression appears as a dark line in the painted surface).

using the "flip" method to copy
a full size drawing

The alternative method, used since antiquity, is to square the picture, and it requires no special equipment or messy copying medium.

first step: squaring the original picture

The first step is to rule a regular grid over the painting to be copied. The total number of squares required will depend on the variety and complexity of shapes in the picture to be copied, and on the degree of accuracy you require — smaller squares make the copying more accurate, but also more time consuming.

You can also rule a coarse grid over the entire drawing, and subdivide one or more of the large squares to capture the details in a local part of the drawing, as shown above.

Although no special equipment is necessary, you can save time with an overlay. Many drafting stores sell vellum sheets preruled with a grid, and on strongly contrasted designs, one of these sheets can be overlaid on the drawing to provide the grid. Some map stores sell sheets of acetate preruled with black lines for reading the intermediate distances on topological maps and the like; or you can buy a sheet of blank acetate and rule or scratch the lines yourself. These transparent sheets work best to copy dark, faded or delicately toned images.

Not only do these overlays save time, they avoid having to draw the grid directly on the surface of the photograph or drawing, which scars it permanently. (If it's an image you expect to copy many times, this may be preferrable.)

squaring and noting the drawing surface

The second step is to rule the drawing surface. This grid must be drawn as lightly as possible, so that it does not emerge through the painting, and does not visually distract you from drawing the lines of the image. I sometimes use medium gray aquarelle pencils to draw this grid, because the lines dissolve when paint is applied over them and the color is very faint.

Ruling this grid gives you the opportunity to change the format of the image. If you want to reduce the size of the image, rule the squares smaller than they are on the original; to enlarge the image, make the squares bigger. You can also change the proportions. To make the landscape image "wide screen," just make the grid spacing rectangular, with the horizontal spacing of lines greater than the vertical. To reduce the size of the foreground, rule the bottom row of squares as rectangles, but leave the rest of the picture in square.

The third step is to note the major line crossings of the image. I find it's easiest to work systematically: for example, from top to bottom of the image, noting the major in the horizontal lines; then left to right, noting the important vertical lines, and finally adding any diagonal lines or details. This helps to avoid omitting important lines, or counting off squares in the grid to identify where a line is located.

All this is done freehand, by eye. You simply make a small mark on the drawing at each point where a line in the image crosses a line in the grid. You can also use short lines to indicate the slope and direction of a line. To improve your accuracy in estimating the location of a point, lay the point of your pencil on the center of a line to divide it into two, and locate the point in the half segment.

connecting the guidemarks with lines

The final step is to connect the guidemarks in the drawing as living lines. Again, I work down the page constructing all the horizontal lines, then across the page working on the verticals. Unless accuracy is important, it's best to use the guidemarks as reminders of how the line is shaped, but deviate from these in the interests of design, simpification or emphasis.

tracing the image

Modern artists have adopted a variety of optical aids to assist in drawing or painting.

Opaque Projectors. Most popular are a variety of opaque projectors or magnifying projectors (which I used and loved in my childhood under the name Magnajector). The current brand names include Artograph, Trace-Master, Seerite and Kopykake; prices range from around $50 up to $630, depending on the quality of the optics, magnification power, illumination source and ventilation system.

Object Projection. Methods for projecting the whole object. In former times a camera obscura worked for this purpose.

tracing the shadow of a botanical specimen

Microscopes have also been used as projection tools, for example in anatomizing microrganisms, minerals or living tissue.

Slide projectors. With the new era of digital cameras and displays the technology of the slide projector has slipped into antiquity. When these are available with slide documentation or source materials, they can be used in the same way as an opaque projector.

documenting with photographs

Photographs had a significant impact on artistic perception because they could visually resolve aspects of the world that were difficult or impossible to see with the unaided eye.

The watershed texts are the many series of analytical photographs made by the victorian photographer Eadweard Muybridge (18-18), who published, as Animal Locomotion (1887), books of human figures and animals in motion, photographed in rapid sequence against an analytical background grid. It was Muybridge who definitively settled a longstanding debate as to whether a trotting horse is ever completely suspended in the air during its gait (the answer is yes).

Flowing water, rippling reflections, the colors of twilight, the wings of the hummingbird and the shape of exploding fireworks are some of the other visual delights that have been exactly rendered in paintings based on the evidence in photographs. And most textbooks on linear pespective will reprint a photograph of railroad tracks or urban skyscrapers as "proof" that perspective is "real."

creative editing of photographs

One of the most exciting possibilities that has been opened up by digital image processing — either directly, with a digital camera, or indirectly, by scanning a photograph or magazine made in the regular way — is the ability to use digital media as a creative tool.

using image editing to reduce detail

The example shows the differences between the original image (left) and the image processed with the Adobe Photoshop "pixelate/facet" utility (right). The pixelation reduces the image to an irregular mosaic of color, simplifying forms and eliminating detailed or complex textures (note the difference in the wisteria blossoms on either side). I find this is particularly useful to analyze shapes into large areas of color, and to reduce complex, detailed textures into simplified, schematic patterns that are easier to paint and to weave into decorative effects.

If you have access to a powerful image processing program, and are willing to learn how to use it, you can greatly expand your compositional creativity. This next example shows how I revised an impromptu landscape photograph into a base image for a landscape painting.

revising image composition: format proportions

Photoshop permits the insertion of a transparent layer, which can be used to draw guidelines or registration marks for shifting image elements; this layer can be blanked out so the image can be evaluated without it. The image above shows the landscape with the grid of format proportions superimposed on it.

The format proportions suggest that the central cluster of trees can be broken up, and the far mountains lowered and reshaped to define the second horizontal. The foreground darks can be lowered somewhat, and the image of the road increased. These changes would all have the effect of increasing the sense of depth and space in the picture, and thereby open the composition to a more emphatic statement of the light flowing from left to right.

revising image composition: before and after

These comparison images show the landscape photo before and after editing. The changes are subtle, but I see a general strengthening of the sense of recession and perspective, a more graceful disposition of masses, better statement of the relationship between the road and the groups of trees in the middle distance, and a better pattern of alternating dark and light bands across the landscape.

The image processing program can also be used to alter values or hues, change color schemes, enlarge or reduce individual objects, reverse objects left to right or top to bottom, and copy a single individual object (such as a tree branch) multiple times to create a complex pattern or texture. Notice that all these changes are what and artist might naturally try out in a value sketch or color study: the difference is that the changes can be made more quickly, and multiple versions of the same image can be compared simply by turning on or off the transparent layers containing each edit.

Landscape Formats. Many contemporary artists are so accustomed to accepting a photograph as the painting representation that they don't consider the many ways that a photo can be altered for dramatic effect.

Landscape painters traditionally "adjusted" the proportions of objects and distances, sometimes by violating or exaggerating linear perspective rules, to produce a more compelling landscape image. These exaggerations are part of the landscape tradition. I often use simple Photoshop transformations to produce a similar effect.

Here's an example from a photo of the nearby California coast, made with the 18mm-70mm zoom lens that comes standard on my Nikon D70 prosumer digital camera. (I adjusted the lens to about 30mm, or wide angle, to make this shot.)

Most digital photographs are now roughly in the format proportion 30:20, which is close to the format of the standard full sheet (30:22), shown as the added black at the bottom of the image. However the technique I describe works for any format, provided you first crop the photo to the image you want, then take that image width to equal the width of the paper format you will use for the painting.

landscape photo against full sheet format

In Adobe Photoshop a simple way to make the formats match would be to select the entire digital image (Command+A), then use the Free Transform utility (in the Edit pulldown menu, or Command+T) to increase only its height by 110%. However this won't eliminate the basic shortcomings of the original image. The distant cliffs appear farther away and lower in height than they impress the viewer in real life, while the foreground rocks are proportionately too large. The viewer seems to look across rather than down onto the surf, and the surf around the promontory seems flat and lifeless. The foreground space seems to flow away on either side, as if running out the bottom corners of the frame.

Here's the cure. Use the Rectangular Marquee Tool to select the entire bottom of the image, from the base of the main middle distance form to the bottom edge (orange rectangle). Then use Free Transform to resize only this part of the image upwards (orange arrow), judging by eye the amount of foreshortening that looks best in relation to the height of the middle distance form. (A reduction of one third, or 66%, is usually pretty effective.)

vertically compressing the landscape foreground

Finally, select the entire image area and use Free Transform again to pull it downwards until it fills the entire full sheet format area. This largely compensates for the previous foreground compression, but vertically elongates the middle distance and background forms.

altered photo resized to full sheet format

Now the distant cliffs rear up and approach nicely, and have more weight in comparison with the foreground rocks. The horizon has been lowered, increasing the proportion of sky to landscape forms. The foreground beach seems to flow under the viewer's feet, and the viewer is pulled into the center of the image. The middle distance surf appears closer and, for that reason, more lively. All the landscape elements are pulled into a tighter, more dynamic relationship, in part by violating the perspective rules for wide angle images that push middle distance objects farther away.

To help you visualize what's been done here, I've performed exactly the same transform on a perspective gradient and square forms (left), producing the altered perspective space (right). The horizon has been dropped and the orthogonals beyond the transformation boundary have been tilted upward. Foreground recession and object proportions have been slightly compressed vertically.

perspective gradient before and after transform

This method translates into a simple drawing procedure when working in the field: elongate distant forms vertically (to make them appear larger and closer) and vertically compress the foreground (increase the foreshortening) by a proportional amount, without changing (or slightly flattening) the proportions of foreground objects.

What's most intriguing is that people familiar with the specific landscape you've painted will prefer the transformed image but will not notice that it has been distorted in any way. This is even true for many buildings or architectural forms, which look more dynamic or impressive when distored in this way.

If landscape buildings or figures appear unacceptably distorted after the transform, simply select and copy that building or figure from the original image, make the standard transform on the surrounding space (landscape), paste the original shape over the distorted one, then free transform the original building or figure image until it has the size and proportions you like best in context.

As you see, it's practical and sometimes powerful to select different parts of the image, resize, transform and reposition them in different ways, then paste them together as a completely new image. You can also horizontally expand certain figures, for example only the boxers in a boxing ring, to make them appear more massive. (Martin Scorcese shot the boxing scenes in Raging Bull using boxing rings of different sizes, in order to produce different perspective and size effects for the camera.)

Analysis of Form and Light. Photographic media can also be used to analyze a great variety of visual problems, in particular by exaggerating or simplifying a complex image in ways that allow it to be painted in a nonphotographic style.

Your resources will depend on the kinds of images and photoediting software available to you. Nearly all digital cameras now are sold with simple photoediting software, and professional painters may find it worthwhile to invest in an industrial grade program, such as Adobe Photoshop. (Most important: play around with the program you have to learn what is possible.)

Here is a simple analysis example that addresses one of the most basic landscape problems: painting a tree.

analyzing a tree using Photoshop image edit functions

top left: original image; top right: filter > pixelate > facet; bottom left: filter > brush strokes > accented edges; bottom right: filter > artistic > cutout

The image at left is probably legible to an experienced painter, but for many painters starting out in landscape painting the tree will be an amorphous puzzle — they can't see the tree for the leaves. Photoshop lets us boil the form down to its essentials.

The specific method I used was: (1) reduce the original digital image to a suitably small format (this is some part guesswork), (2) simplify the image structure using the Pixelate: Facet utility, then (3) boost both the brightness and contrast (with the Adjust Image: Brightness/Contrast utility) to obtain a clear definition of the form. (Blurring and then contrasting the image can produce similar results.)

Transformed, the image resolves into interlocking forms that can be obviously painted as a jigsaw of flat color areas. The dark "holes" where we can see into the interior, deeply shaded part of the tree are clearly located, the terminator between lighted and shaded exterior leaves is accurately defined, all the color areas resolve into a basic color containing random touches of lighter, yellower or redder accents, and we even discover an unexpected detail — those near white reflections in the topmost branches.

Cameras are not the arbiters of your artistic vision unless you choose to make them so. Yet it's incorrect to say that these computer manipulations are different ways of representing reality — reality is only "represented" within the mind, not outside it. I've described methods of filtering or distorting the rich information presented to us by the world, via made images, in a way that affects the viewer's perception in artistically desirable ways.

representing the world

When David Hockney began is research into the early use of optical projection devices, he was initially struck by the unique appearance of drawings and paintings that might have been traced from the images projected by lenses or mirrors. Drawings lacked the hesitancy, trial and error lines and erasures; paintings had unique qualities of physical detail.

With photographs, too, new areas of visual detail finally could be realized: the gait of a horse or the leap of a cat, the weave of watery reflections.

two opaque projectors

Artjector student portable model (top); Kopykake professional table top model (bottom)

At each step, artistic application of the technology also inserted clumsy misinterpretations: paintings showed peculiar lapses in figure proportions or posture, because the optical devices required separate, limited projections fitted together. An early painting by Thomas Eakins, of horses trotting, is absurdly unreal.

The point is that the artist never surrenders the responsibility of choosing the informative moment and view used in the image. A photorealist painting of a diver at the beginning of his release would look as comically peculiar as Eakins' trotting horses: the diving board curving downward under his feet, both arms out and knees flexed, as if steadying for a fall.

Actions have their moments of inflection, of emphasis, of maximum dynamic potential: the dive becomes visible when the diver in the air, not when he is in his preparatory squat. At the end of parking a car, the driver is merely sitting in the car, as if waiting for someone to arrive; at the end of a fight, the assailant may approach his prostrate victim in the same way a good samaritan might approach someone who has fallen accidentally. Artists choose the moments that make things clear, or intentionally prosaic and ambiguous, and this is something the technology can never do.

It's wrong to say that these are different ways of representing reality — reality is only "represented" within the mind, not outside it. Rather, they are ways of filtering or distorting the rich information presented to us by the world, summarizing and abstracting reality in ways that provide esthetic impact.

misjudged photorealism in Thomas Eakin's "A May Morning in the Park" (1880)