An Instrument for Showing the Contour of Paper Surfaces.

The Proficorder is an instrument designed to draw an enlarged profile of metal surfaces. It is also useful for drawing the profile of paper surfaces. The instrument uses a probe stylus attached to a differential transformer, and is different from other similar devices using crystals, in that there is no decay factor. It draws a true profile showing irregularities of long wave length, and also enables the rate of travel of the probe to be reduced so that the finer detail in the paper surface may be indicated. The graphs of contour of paper surfaces obtained by this method show several characteristics associated with printability. Examples demonstrate coating pile, smooth and rough formation and holes in the surface. Surfaces of cast coated paper and other printing papers are shown.