Accurate Drawing
What makes a drawing come to life? A drawing comes to life when it is accurately rendered to depict proper perspective. This includes understanding the viewpoint and angle of the subject, creating volume by following the surface contour, applying light to the object to create gradations of tonal value, and studying surface texture, color, and details.
Perspective
Perspective, as it pertains to drawing, means recording a three-dimensional object on a two-dimensional surface to render a realistic appearance of the object in life by accurately representing all aspects of the object through proper perspective and skill. To make the translation from reality to paper, it’s vital to learn the rules of perspective. We’ll start with the picture plane, which is an imaginary, flat, transparent plane held parallel to the artist’s angle of vision and the subject. The subject can be seen at, below, or above eye level. Shown below is a box at, below, and above the artist’s eye level.
The Picture Plane
Note that the head is tilted to correspond with the viewpoint. Any shift or change results in a “different” picture. While drawing and measuring, it’s essential to stay within a fixed viewpoint.
Simple Forms
It’s easy to see how the basic geometric forms originate from a box.
The cone has a flat bottom, but the sides are no longer parallel to one another. They converge at the top.
The cylinder has a flat bottom and top. The four walls of the cube round to form the cylinder.
On a perfect cube, all six sides are the same size. The sphere touches each plane of the cube in the center, indicated by the green dots. There is no longer a flat surface, as the surface contour has changed dramatically.
Surface Contour
Think of surface contour as a topographical map of an object. To clearly see the surface contour, it helps to create an armature drawing. An armature drawing shows how the different planes move, curve, and shift. Look at the basic forms below. Each can be broken down into specific planes or surfaces, and the shape of each surface changes as lines transform from straight to curved.
In a box, all the surface contour lines are straight. The blue lines depict the vertical terrain, and the pink lines depict the horizontal terrain. The top of the cube is also flat, with straight green lines.
In a cone, the pink horizontal lines remain ellipses. The blue vertical lines stay straight, but because the top of the cone is pointed, all the vertical lines converge to the top. The flat top and green lines disappear.
In a cylinder, the blue vertical lines remain straight. To depict the “roundness” of the cylinder, the pink horizontal lines are now ellipses. The top of the cylinder has changed from a rectangle to a circle. The top is still flat, and the lines are divided into slices radiating from the center axis, rather than a grid.
In a sphere, there are no straight lines. All the lines are ellipses. The blue lines depict the vertical terrain, and the pink lines depict the horizontal terrain.
Lighting a Subject
Once you understand the surface contour of an object, apply light to create form and bring it to life. Botanical and scientific illustration requires a consistent light source for uniformity. On any given day or time of day, the light can change. When you’re working indoors, setting up a consistent light source allows for optimization of form.
If possible, use a light that recreates natural sunlight. I recommend using an OttLite, because its soft, natural light creates diffused cast shadows.
Setting the Light for Optimum Results
Below is a comparison of two different lighting setups. The photographs have been converted to grayscale so that it is easier to see the comparison.
11:00 Lighting Light is directed from the left at 11 o’clock, with the light raking from the left side and down. Take a closer look at the onion, and notice that the highlight is found at the upper left. The right side is much darker than the left, with details missing in the darker areas. The shadow is elongated and dominant.
11:00-at-45-Degrees Lighting Here, the light remains at 11 o’clock but is shifted 45 degrees from the picture plane. Notice the subtle differences. The highlight is still in the upper left of the onion. The left side is lighter than the right, but more details are visible on the right side in the darker areas. The shadow is smaller and recedes in space.
The second lighting setup gives the best form and detail to work from. I highly recommended setting up your subjects like this to create the best scenario. Over time it becomes possible to imagine this kind of lighting in your mind’s eye and you can apply it to any subject, whether you are working with a studio setup, ambient light, outdoors, or negating the light source in a photograph. The goal is to always be consistent.
Simple Forms with Light Source
The photographs here show how light hits these plaster forms using the 11:00-at-45-degrees angle. As you have seen, the surface contour is different for each subject. Notice how the light source shows the difference in the shapes of the highlights, middle, and shadow areas, as well as the shapes of the reflected highlights and cast shadows.
Cast Shadows
In botanical and scientific illustration, the subject typically floats in space. Depicting your subject on a surface results in a cast shadow, which eliminates the appearance of floating. Cast shadows also appear when one subject is in front of another—for instance, one leaf in front of another leaf. The leaf in the foreground casts a shadow onto the leaf in the background.
In this diagram, notice that the gray back side of the cube casts the shadow onto the surface. The length of the shadow is determined by the height of the cube and the 45-degree angle from the left back corner.
When one object is placed in front of another, the shape of the cast shadow conforms to the shape onto which it is cast.
The cone in the front is casting a shadow onto the flat plane of the cube. Since the plane is flat, the cast shadow does not vary from the shape of the cone.
When the cone is placed in front of the sphere, the cast shadow conforms to the shape of the sphere's surface contour, which is round.
When a cylinder that is much taller than the cube is placed in front, the cast shadow folds over the flat surface of the cube’s top.
How Surface Contour & the Light Source Work Together
This series of graphite drawings depicts three pumpkins and the subtle differences in their overall shape and surface contour.
This pumpkin is more compressed, and the sections are more defined. Each section bulges out in the center and tapers toward the stem and bottom. Each section has a highlight, but as the sections move away from the light source, the highlights and shadow areas darken.
This pumpkin is spherical, or egg shaped. It is smooth all the way around. I applied graphite in the direction of the surface contour.
This pumpkin has undulations and sections. The surface contour is no longer smooth, and each section receives light in a different way as the terrain of the pumpkin changes.
How Light Affects Color
Working in graphite helps us learn how to understand and properly render light, form, and texture. Working in graphite is considered monochromatic, or one color—that color is gray.
Every color has its own value range, as demonstrated in the color and value wheels here. For example, yellow has a very narrow range and blue has a broader range. The key to extending the range of a color without changing it into a different color is through accurate, interesting color mixing.
Local Color
Local color is a description that generally states the basic color of an object. The apple is red. The flower is yellow. The sky is blue. These are examples of local color. An artist needs to represent both form and true color representation simultaneously. There are many options to consider.
The six spheres below are rendered in colored pencil. The local, or main, color is true blue (PC903) by Prismacolor. True blue is a medium-range blue that contains some green, rather than purple.
Here is a breakdown of the different approaches to extending the range of color, while still maintaining the local color.
a Monochromatic This method uses only one pencil. In this example, I used true blue (PC903) to apply color in gradations of tone following the surface contour. This method is identical to working in graphite.
b Monochromatic with a Colorless Blender Overlay This method is identical to the monochromatic method, but is finished with a top layer of colorless blending pencil over the entire sphere. Notice that the color is much more vibrant. The blender eliminates the texture of the paper and intensifies the color.
c Analogous This method uses different colors of blue, all within the same green-blue category. Instead of varying the layers and the pressure, I used lighter shades of green-blues. I used true blue overall to maintain the local color, peacock blue (PC1027) in the middle and shadow areas, and indigo blue (PC901) in the deepest shadow areas.
d Undertonal Painting This method uses a darker neutral color to create form in a monochromatic application. Once the form is rendered, apply the local color on top of the undertonal drawing. In this example I used light umber (PC941) for the undertonal drawing, with true blue on top.
e Complementary This method uses colors that are opposite one another on the color wheel. When mixed together, complementary colors can also turn “muddy,” so this method can be challenging. Here I used true blue and cadmium red hue (PC124), an orange-red. Apply the colors in alternating layers, and use cadmium red very lightly to avoid muddying the local color.
f Triad This method uses colors that create a triangle on the color wheel. In this example, I used three colors: canary yellow (PC116), pomegranate (PC195), and true blue. Canary yellow is an orange-yellow, and pomegranate is a red-purple. Use all three colors in alternating layers. True blue remains the dominant local color, but now different amounts of unusual color can be seen through the layers.
Complicated Surface Contour
When the terrain of a subject is more complicated, it’s important to understand that the light source must follow both the overall shape of the subject as well as the smaller shapes within the subject. Below are a couple of examples.
This artichoke is basically a globe sitting on a cylinder. While the overall highlight is at the upper left, the surface texture plays a huge role in how light hits the overall shape. Look at the surface contour of each section. Each leaf casts a shadow onto the one behind it. As the overall form turns away from the light, it gets darker.
This red pepper is basically a cylinder shape with odd twists and turns. The surface texture is shiny and smooth. Shown here is a breakdown of the armature drawing, tonal drawing, and final watercolor painting.
This step-by-step demonstration breaks down how to render the artichoke in watercolor. The color scheme is analogous, with accent colors added for details.
Apply a generous layer of water to the entire surface, including the stem. Using the tonal drawing shown here as a guide for the light source, add the shadow areas. Be sure to preserve the highlights. Work the entire area while it’s wet.
Allow the paint to dry, and then apply a darker mixture of green paint to strengthen the shadow areas, using a semi-dry brush technique (see here).
Strengthen the form by using the dry-brush technique to introduce subtle color variations, such as purples and browns, to add interest and character.
Finish the color, form, and details with a smaller detail brush.