iraf.net

Hi Daniel,
The SGI graphics kernel (note this is different than the SGI trans-
lators) does have a limitation that prevents you from specifying a graphcap
at full 600 dpi resolution, the code was written when 300 dpi was high end.
However, nearly all IRAF graphics are vector plots and don't really require
this kind of resolution (which only makes a difference for images), 600 dpi
printers are in regular use here and elsewhere. Image generation routines
such as IGI, the EXPORT task, or hardcopy from SAOimage/XImtool don't rely
on the SGI kernel and can make use of 600 dpi devices in other ways.
To install a 600 dpi printer in IRAF just write a graphcap as you
would for any postscript device, i.e. the final link is to the generic
(300 dpi) "sgi_apl" graphcap entry (see the 'lw16' entry in the distributed
graphcap). I'd have to check but I'm not sure PS supports more than 8-bit
pixels so I'm not convinced you'd really get more grey tones, or if you did
that you could really tell the difference.Cheers,
-Mike

> I'd have to check but I'm not sure PS supports more than 8-bit
> pixels so I'm not convinced you'd really get more grey tones, or if you did
> that you could really tell the difference.

I meant, of course, aside from 24-bit RGB images. Grayscale or
PseudoColor I don't believe PS supports more than 256 colors in 8-bit mode,
there are those who argue the eye can't differentiate more than 64-128 colors
anyway and I've gotten perfectly reasonable image with <128 colors in the past.
600 dpi gets you really nice black tones in images but for vector graphics
there is no difference I can tell, publication-quality graphics do improve
with 600 dpi printers but you'd have to tell me what you're trying to
accomplish before I can say how best to get there.-Mike