One of the concepts that can be difficult to grasp in AutoCAD is the use of different drawing scales.  Drawing scales are used to relate the size of the object being drawn to the image on the paper.

When drawings were created by hand, the object may have been drawn at the same size or smaller or larger than the actual object to fit properly on a piece of paper.  Annotation and symbols were drawn the same size, regardless of the object scale.

CAD has changed the way that drawing scales are applied.  Objects may now be drawn at their actual size in the CAD file and reduced or enlarged when printed.  The size of annotation and symbols vary depending on the printing scale.  For instance, if a drawing is printed at 1/2 its actual size, text that is 1/8" in the CAD file will appear 1/16" on the print.  To have the text print at a height of 1/8" it must be drawn 1/4" in the CAD file.  Surface texture symbols, revision symbols, balloons and other symbols would be drawn or inserted at twice their intended printed size to appear correctly on the print.  The border, title block and other charts would also be drawn or inserted at twice their printed size.