Tech Biz Writing

Perspective is an artist’s attempt to come to terms with the world as it exists. To represent objects in space as they really are — or seem to be — on a flat plane (paper or screen), various expedients have to be employed. The essence of it is to project the three-dimensional object onto the two-dimensional surface in such a way that the apparent linear relationships of receding planes are maintained, or, in some cases, exaggerated. There are three types of linear perspective:

* One-point (parallel)
* Two-point (angular)
* Three-point (oblique)

For a cube the first would show one face only; the second would show two; and the third, three faces. Distortions would appear if a one-point drawing showed two faces; two-point showed three faces, and so on. Only three-point perspective allows a true depiction of three faces of an object. For this reason it’s usually used in technical illustration.

Photographs may also be used for line drawings as a guide for the illustrator. This is not as simple as it sounds since there are many problems associated with camera angle and obtaining the right axis or axes through the equipment. Photographic prints may be useful as a simple introductory guide for exploded views or cut-aways.

A further technique is to draw in the outlines and relevant details on a photographic plate with ink, and to bleach out the image with potassium ferricyanide leaving the line drawing intact. This is not frequently used in technical work nowadays, but it can be cheap and effective in certain circumstances.

Next: 39. Half-Tones

This entry was posted on Sunday, July 30th, 2006 at 7:19 pm and is filed under Technical Writing, Business Writing, Publishing, TechBiz Writing, Educational Textbooks, Software, Documentation, Design, Photography, Illustrations. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.