Dialog Box - called from: Direct Postscript Output Dialog, Settings Menu
The page size, page margins and dots per inch/centimeter should be determined by the actual printer used for final output; if these are not correct, the drawing may not be scaled and/or placed on the page correctly.
The Transfer Function is analogous to the PostScript function of the same name. The linear option is standard; modify the function to get lighter or darker shading in PostScript print-out.
Preview Color. If you select a screen preview (TIFF bitmap or PICT sub-file) in the Direct PostScript Output dialog, and if color output is selected, you can specify either a color or black-and-white bitmap. The Screen option uses the color depth of the the current screen display. Black-and-white PostScript output always uses a 1-bit or black-and-white screen preview.
Background color. If this option is on, the color selected in the Background Color dialog of the Input2 Menu will be applied in color output only. Background in b/w output is always white.
Atom algorithm. ATOMS shows shading for atoms by computing concentric zones around the point of emergence of the illumination vector. This can be done in two ways: 1) For non-PostScript display and output, points are calculated on lines radiating outward from the point of emergence. This means that the curves defining atoms and atom shade zones are defined by a large number of short line segments - this is called the "lengthy" algorithm. 2) The default algorithm for Postscript, called the "compact" algorithm, simply sends the parameters for the circle and ellipse segments which make up these curves (this cannot be done for normal drawing because the system drawing routines do not deal with general ellipses). The lengthy algorithm typically requires twice the disk space as the compact algorithm for shaded atoms. The compact algorithm is also more precise in its drawing of curves, and it allows all illumination vectors (for the lengthy algorithm, the point of emergence of the illumination vector must be within the atom outline, which may be truncated by interpenetrating atoms or large stick bonds). The only case in which the lengthy algorithm might be necessary is when three or more atoms interpenetrate, so that the segments removed from the outline of an atom overlap. This condition in principle could also arise if two stick bonds to an atom overlap.
---- Windows only ----
If you are using direct output to a printer you must select the Port; this will be either "LPTn" or "COMn". Also, if you are using a serial port for the printer, you must set or verify the data transmission parameters, such as baud, parity, etc., even if the port currently shown is the correct one. This is done in the Ports item of the Windows Control Panel (not in ATOMS).