MacOS Preview Warning
---------------------

Low-resolution raster-images appearing in PDF or PostScript files may look blurry when viewed
with the Preview application under macOS. This happens because Preview decides to resample very
coarse (low dpi) images instead of leaving them alone; we do not know of a simple way to turn
this feature off.  It is most noticeable in color bars for discrete CPTs (we now use **-Np** as
the default setting for such CPTs) and very small grids plotted in either :doc:`grdimage` or
:doc:`grdview` **-Qi**\|\ **c**. However, if a raster format (such as JPG or PNG) is selected instead
then here is no such blurring.  Other PDF viewers (e.g., Adobe Acrobat) do not seem similarly affected.
