Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!gatech!prism!robert@shangri-la.gatech.edu.gatech.edu
From: robert@shangri-la.gatech.edu.gatech.edu (Robert Viduya)
Newsgroups: comp.lang.postscript
Subject: Re: Getting 255 Grey Levels
Message-ID: <362@hydra.gatech.EDU>
Date: 24 Mar 89 15:42:02 GMT
References: <1597@murdu.oz> <854@draken.nada.kth.se> <402@helios.prosys.se>
Sender: news@prism.gatech.EDU
Reply-To: robert@shangri-la.gatech.edu.gatech.edu (Robert Viduya)
Organization: Office of Computing Services, Georgia Tech
Lines: 15

> Perhaps it should be added that 255 grey levels aren't very useful for
> human 'consumtion' - the eye can't distinguish between more than about
> 30-50 levels of grey.

Try creating a completely white to a completely black fade effect using only
30 levels of grey.  This effect is known as a fountain and using only 30 levels
of grey produces an ugly banding instead of the desired smooth transition.

			robert

--
Robert Viduya					   robert@shangri-la.gatech.edu
Office of Computing Services
Georgia Institute of Technology					 (404) 894-6296
Atlanta, Georgia	30332-0275