ABSTRACT
Blueprints, as working or production drawings are generally termed, are photographic reproductions of an original drawing. They take their name from the colour of the finished print when the drawing is reproduced on ferroprussiate paper. This paper produces copies of the drawing in white lines on a blue background. Several other types of coloured prints are also produced by industrial contact photo equipment, but in spite of their colour these are still generally known as blueprints. The practical body worker is rarely called upon to produce a finished drawing, but he will find it necessary in many cases to understand and work from both general and detailed drawings as set out by a skilled draughtsman. The main object of reading a drawing is to obtain a clear mental picture of what
of a conventional arrangement of lines and symbols. To this end the value of hand sketching cannot be too fully emphasized, as well as the making of simple models, for a much clearer impression of form can be obtained when movement and touch are combined with sight. The skilled craftsman, particularly in the small workshop or garage, is generally responsible for seeing his work through all stages of manufacture, commencing with careful study and accurate interpretation of the drawing. Before actual manufacture can begin, it is necessary to set out the desired shape by marking the outline on the surface of the sheet of material.
