The Virtual Machine Shop

Blueprint

A generic term for the representation of the work piece to be manufactured. It can be a pencil sketch or a CAD drawing or any of a number of other graphic options used to represent the design.

The blueprint was orginally blue with white lines expressing what was drawn on the paper. The paper used was semi transparent so the the pencil lines blocked light from passing through. The drawing was laid onto chemical print paper and exposed to a strong light which turned the paper blue except where there were drawn lines. So after this process a drafting document produced a blue copy like the following:

Eventually the process was reveresed to that the blue became white and the white became blue like this:

Today the chemical process of light exposure is gone replaced by plotter output from a CAD file.

Yet the word "blueprint" has remained as a generic word of description

be machined. It can be a pencil sketch or a CAD