Posted-Date: Mon, 28 Dec 92 16:33:31 -0500
Date: Mon, 28 Dec 92 16:33:31 -0500
From: lpmazda!dan@uunet.uu.net (Daniel Wasserman)
Message-Id: <9212282133.AA00791@ lpmazda >
To: uunet!aero.org!rman@uunet.uu.net
Subject: rendering resolution in RGB or CMYK

Donovan Kolbly writes:
> Also, are there any commercial "rendering services" available, which 

> for a nominal fee would render our .rib files at 2400 dpi or so.

Malcolm Blanchard writes:
>Unfortunately, I can't answer Mr. Kolbly's direct question, but I want to
>comment on his desire to render at 2400 dpi.  Since Photorealistic RenderMan
>(and most other renderers) produce continuous-tone (con tone) output, there
>is very little need to ever render an image at anything near 2400 dpi.  A 300
>dpi con tone should be sufficient for most imaginable needs.  Imagesetters
>operate at 2400 dpi, but they need this to produce smooth line work and text
>and to build up accurately shaped and placed half-tone dots.  For half-tone
>reproduction, the rule of thumb is to produce a con-tone image at twice the
>resolution of the half-tone screen.  Most magazine and catalog work is
>reproduced at 150 line-pairs/inch.  Thus they need con-tone images at 300 dpi.
>High-quality art reproductions may reach 300 line-pairs/inch, but at that
>resolution the 2x rule of thumb breaks down and you could probably still get by
>with a 300 dpi con-tone (although 400 dpi wouldn't hurt).

Can Renderman render in anything else but RGB?
If it can't you/we will need a conversion program for CMYK. Mind you the NeXT  
color picker is brain damaged when it comes to CMYK color. What the NeXT color  
picker is doing is converting RGB to CMY (no K). This is a very complex issue, I  
would be happy to discuss this further with any one; but, since it is not Renderman  
specific I will just leave it be.

Daniel Wasserman
NeXT High Resolution Service Bureau and Printing Company
uunet!lpmazda!dan
or
LightPrinting@gun.com