[comp.sys.amiga] A500 Monochrome?

scottw@ico.UUCP (Scott Wiesner) (06/22/87)

Hi,

I may have missed some discussion on this already as I think our site missed
a bunch of news last week...

I understand the A500 has some kind of monochrome port on the back that was
not available on the 1000.  Does this mean if I buy an A500, I'll be able to 
get good high quality (jitter free) 640 X 400 resolution on an inexpensive
monochrome monitor?  

I've been considering buying an Atari ST (1040 or new Mega), but the pricing
of the A500 is tempting, especially if I can get good monochrome output.  

Scott Wiesner
scottw@ico.isc.com

cmcmanis%pepper@Sun.COM (Chuck McManis) (06/23/87)

In article <1236@ico.UUCP> scottw@ico.UUCP (Scott Wiesner) writes:
>Hi,
>
>I may have missed some discussion on this already as I think our site missed
>a bunch of news last week...
>
>I understand the A500 has some kind of monochrome port on the back that was
>not available on the 1000.  Does this mean if I buy an A500, I'll be able to 
>get good high quality (jitter free) 640 X 400 resolution on an inexpensive
>monochrome monitor?  
>
>I've been considering buying an Atari ST (1040 or new Mega), but the pricing
>of the A500 is tempting, especially if I can get good monochrome output.  
>
>Scott Wiesner
>scottw@ico.isc.com

Yes, this is essentially true. What has happened (and George correct me
if I am wrong), is that the Amiga 500's composite video output is monochrome.
HOWEVER, they did not just 'turn off' the Color Burst, rather they
mix Red, Green, and Blue at a fixed ratio to generate true gray scales 
rather than simple colorless colors. What this means is that if you have
a light green bar and a light yellow bar side by side they will appear
as *different* shades of grey on the monitor, unlike the Amiga 1000 which
would send this out as 'color' to the monochrome monitor and both bars
would appear to be identical shades of grey. Thus Commodore has apparently
attempted to give you your cake, (color graphics) and let you eat it too
(high res mono, if you buy an inexpensive high persistence Mono monitor).
What they did not do, and I suggest they consider it for 1.3, is make
workbench understand 400 line screens better. I suggest that selecting
'Interlace' (relabeled to High Resolution) should also do the equivalent
of 'Setfonting' a slightly taller font in the workbench screen. One might
also wish for an icon that could display a 'hi-res' version if the interlace
mode was on. The text clarity should be better than the Atari because you
get shades of grey for free (which the Atari cannot do in it's current 
state). If you want color Composite video, may I suggest you consider
adding a Genlock (Memetics possibly because the A1300 wont fit) which
produces Composite Color video (as well as lots of other wizzy things).


--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.

grr@cbmvax.UUCP (George Robbins) (07/08/87)

In article <1236@ico.UUCP> scottw@ico.UUCP (Scott Wiesner) writes:
> 
> I understand the A500 has some kind of monochrome port on the back that was
> not available on the 1000.  Does this mean if I buy an A500, I'll be able to 
> get good high quality (jitter free) 640 X 400 resolution on an inexpensive
> monochrome monitor?  
> 
> I've been considering buying an Atari ST (1040 or new Mega), but the pricing
> of the A500 is tempting, especially if I can get good monochrome output.  

Yes, the A500 has an RCA jack for composite monochrome output in addition to
the RGB output.  To my perception, it is essentially free of objectionable
flicker when used with a medium/long persistance green or amber monitor.  I've
seen suitable monitors advertised in the computer shopper for $75-150.

Note that different people have different threshold levels for flicker.  You
do need a longer persistance monitor - with "TV" speed phosphers it's not
much fun in interlace mode, although it's fine other modes.

Further note that composite monochrome is not the same a "PC Monochrome",
composite monitors were being sold for monochrome graphics output from a
PC CGA card a few years ago, but that's died down since the Hercules clones
made better PC graphics available...
-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)