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Posting-Version: version B 2.10.1 6/24/83; site wateng.UUCP
Path: utzoo!watmath!watdaisy!wateng!ksbszabo
From: ksbszabo@wateng.UUCP (Kevin S. B. Szabo)
Newsgroups: net.analog
Subject: Re: Help with Graphics Monitor Design - (nf)
Message-ID: <612@wateng.UUCP>
Date: Wed, 14-Dec-83 15:58:38 EST
Article-I.D.: wateng.612
Posted: Wed Dec 14 15:58:38 1983
Date-Received: Thu, 15-Dec-83 02:44:14 EST
References: <4452@uiucdcs.UUCP>, <125@watrose.UUCP>
Organization: U of Waterloo, Ontario
Lines: 26

I would just like to comment further about the `smearing'
which occurs with long persistence phosphour. Robert Pike
(one of the creators of the BLIT) mentioned that they
used long persistence phosphour on their bit mapped display.
Smearing is due to the decay time of the phosphour. The
`attack' time (turn on time of the phosphour) is very
short, probably the same as fast phosphors. Hence if your
text is in reverse video the time for a line to erase
(as might occur when scrolling) is the attack time of
the phosphor, and the time for the line to become visible
is the decay time of the phosphor. Apparently the 
effect of the phosphor fading to show a new line is
not nearly as annoying as the fading/smearing of previous/erased
lines. You might notice that all bitmapped displays (to my knowledge)
use reverse video. This may be due in part to the above point.

Caveat: I have not seen a blit, so I have not been able
to judge for myself whether the long persistence phosphor
is reasonable.

P.S. I might have mispelled `phosphor' through this document.
please ignore ( I can't stop vi and run spell! damn vi won't let
you use ^z and redefine the stop character.....oh well).

-- 
	Kevin Szabo  watmath!wateng!ksbszabo (E.E. U of Waterloo)