c2x: Publication Quality
A few hints and tips on how to get the best images for publications.
XCrysDen
Do select a white background, via the coloured button to the left of the File menu.
Do choose a reasonable degree of tricubic spline for any isosurfaces. This can greatly increase XCrysDen's rendering time, particularly if there is a lot of vacuum around.
Do make the window large: it will be dumped as a bitmap.
"Print" to a PNG, and then use bmp2eps to convert to EPS or PDF. Don't be tempted by the EPS/Bitmap route offered by XCrysDen - it fails to compress properly, resulting in files which are over twenty times as big as necessary for no gain. Don't be tempted by JPEGs, unless you like fuzzy edges. Don't be tempted by the EPS/Vector route either: for something simple, such as the ethene pi bond, its output is a mere 10MB, and the quality difference over the bitmap route recommended (under 300KB) is noticeable when printed at A4 size. However, at anything less than a significant fraction of A4, particularly if one can get the anti-aliasing option for the bitmap (Print Setup) to work, it isn't useful.
For some surfaces, playing with the "revert normals" and/or sides buttons in the isosurface dialog box is useful.
Fonts look ugly when printed as bitmaps, so for best results, remove all labels, and add them later as proper vector objects using xfig or similar.
Jmol
As for XcrysDen above. White backgrounds can be chosen by right-clicking on the canvas, and selecting color, background, white. File, export will save a bitmap, with png being a much better choice than JPEG, unless one wishes all sharp edges to become fuzzy.
The creation of PDF or EPS from bitmaps, including PNGs
Unsurprisingly I would recommend bmp2eps. Afterall, I did write it.