Printing
DS9 provides strong Postscript printing support. This is not
a screen capture method, but a full level 1 and level 2 postscript driver.
The postscript images generated are detailed and accurate as possible,
given the resolution of the data, and the printing resolution.
Postscript Level
Level 1-- The postscript generated consist of a color lookup table and
image data, encoded in ASCIIHEX. All line graphics and text are
postscript elements.
Level 2-- The postscript generated consist of a color lookup table and
image data, compressed with RLE, and encoded in ASCIIHEX85. All
line graphics and text are postscript elements.
Postscript Color Model
DS9 supports three color models for level 2 postscript. All three color
models generate approximately the same size files.
RGB
CMYK
Grayscale
Resolution
Most printers dither to achieve various levels of gray or color. So a 300
dpi printer's affective resolution may only be 53 dpi after dithering.
This is fine for analysis and proofs. On the other hand, when generating
images for publication, color separation is used to achieve the full resolution
of the printer . A 150 dpi CMYK image will generate four 150 dpi images
(one for each color). For example, ApJ requests submissions be postscript
level 2, CMYK, 300 dpi. In reality, 150 dpi is more than adequate. See
Guidelines
for Authors Submitting Electronic Art Files In general, select
the lowest resolution possible, as postscript file size grows by
the square of the increase.
53 dpi-- use for 300 dpi printers
72 dpi-- use for 600 dpi printers
75 dpi-- use for 600 dpi printers
150 dpi-- use for publication
300 dpi-- use for publication
600 dpi-- use for publication