In our printed publications, figures don't always look exactly like the ones the author submitted. Sometimes, quality seems to have deteriorated. Here are a few reasons, and some suggestions to authors to help avoid these problems.
Rescans don't reproduce cleanly
Hard-copy art submissions that previously were scanned or separated for reproduction via offset lithography or for color plotting never reproduce well in reseparating (rescanning). Rescanning separates the original dots into new dots, which generally yield a moiré pattern and/or inappropriate color. To avoid this problem, redraft and submit work as original .ai, .tif, or .eps files in no less than 300 dpi.
Improper resolution in drafting is a common problem
Many computer draftsmen/geologists work at a resolution of 72 pixels per inch (ppi) and submit their images on disk. This resolution is adequate (and is the default resolution) for RGB CRT imaging, but it is completely inadequate for offset printing, which recommends a resolution of 300 ppi (also known as dpi).An image generated at 72 ppi cannot be successfully resampled up to a resolution of 300 ppi. The best reproduction can be achieved by drafting at a high resolution, and exporting the art at that resolution. You cannot work at a low resolution and change resolution for exporting—the quality will be incredibly poor. The lowest tolerable resolution without too much visible degradation is 300 ppi.
Obscure typefaces on maps and charts may not print
If we or production lack a typeface, the type will either be bitmapped or Courier will be substituted. Design your charts and maps using the common families of type, such as Helvetica, Times, or Palatino.