Realistically rendering machine parts, mechanisms, or systems requires more
precision in certain applications than pictorial rendering. In the illustrations
that appear in operating instructions, manuals, visual aids, or medical
journals, accuracy and correctness are imperative.
Technical illustrations factually or symbolically illustrate the construction,
function, or operation of a machine, a physical phenomenon, an industrial
process, or a biological theory. Accuracy is essential. Even the colors of the
object are often dictated by the object itself, leaving little opportunity for
The technique used to render technical illustrations depends on the way the
illustration is used or reproduced and the time allotted for the job. Airbrush
is particularly suited to technical illustration because of its flexibility, ease of
control, shading, and color blending capabilities.
Make the initial drawing on paper. Do all corrections on the paper drawing
before transferring it to illustration board. Any irregularities caused by
corrections, abrasions, and dirt will show on illustration board.
detailed shading on the paper drawing. Trace the line outline to illustration
board and ink in using any drafting tools required.
Since shading has been predetermined, you may begin airbrushing anywhere
on the drawing. Generally, start at the top of the illustration and work down
or from the left side to the right in order not to disturb completed areas. You
may expose more than one section of the drawing if the sections are not
adjacent to each other and the spray pattern is not large.
Once the drawing is inked onto the illustration board, cover selected areas
with frisket and cut the frisket only along the black outline of the object.
Should the frisket pull away some of the black outline, it will be easy to
correct with an ink pen.
In rendering technical illustrations, your knowledge of rendering the four
basic shapes with an airbrush is invaluable. Approach each section as a basic
form remembering always from where the light originates.
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