On Fri, 14 Apr 2000 14:35:47 -0500, Clarence Verge wrote:
> Samuel W. Heywood wrote:
>> There is no such thing as VGA monochrome, because all VGA monitors are
>> either gray-scale or color monitors. All monochrome monitors are, by
>> definition, two bit displays (i.e. 1 or 0) Monochrome monitors are not
>> gray-scale monitors.
> Hello Sam;
> I'm afraid you are QUITE wrong there. Monochrome means one color NOT one
> intensity. MY VGA monitor is MONOCHROME as per the above definition and
> also as per its' specifications.
Hello Clarence,
Once I thought I was wrong, but I was mistaken.
I know that it is possible for me to set up a mode in my VGA monitor whereby
it will produce the same apparent output with regard to color as an MDA
monochrome monitor; however, my monitor is capable of color, and it is
capable of continuous-tone grayscale also. Regardless of whatever mode
in which I decide to run my monitor, it is still a color VGA monitor.
> It, being VGA, is obviously capable of grayscale. (also as per spec.)
Grayscale means continuous-tone, as in a B&W photograph. This is not the
same as monochrome. Monochrome monitors produce one color, thereby
being capable of producing images resembling those seen in monochromatic
film positives and negatives, used in the commercial printing and graphic
arts industry.
I did not say that monochrome means any more than one color, as per the
literal meaning of the term, being "one color". I did say that some
pixels in a monochrome monitor may be set for intense and bright, while
others remain at a regular or normal intensity. Also I had stated
earlier that all VGA monitors are capable of grayscale or color, but some
are not capable of both, unless you think of shades of gray as being
colors. VGA is capable of continuous-tone grayscale. Monochrome can
produce but one color, by definition. I did say that Hercules monochrome
can produce the "illusion" of grayscale, but everyone knows that a mere
illusion is not the real thing. Therefore, there is no argument.
> The two bit displays (sic) that you refer to are more accurately called TTL
> monitors.
TTL is a type of IC chip, very widely used in the early 1980's. Maybe they
are so called because they have a lot of TTL chips in their circuit boards.
I don't know if this is the reason.
There is nothing wrong with calling a monochrome monitor a two-bit display,
because all of the pixels are either on or off. Even a light bulb can be
considered a two bit display. On = 1, Off = 0. If you increase the voltage
to the filament, thereby resulting in an increase in the intensity of the
light-bulb, it is still just a two-bit display. (A light bulb may also
be properly called a binary display. Binary means "two". The light bulb
will always present itself under only one of its two possible conditions,
on or off. If it is dim, then it is on.)
BTW, do you know how many psychiatrists it takes to change a light bulb?
Well, the answer might surprise you. It only takes just one psychiatrist
to change a light bulb, but only if the light bulb really *wants* to change.
> Although the original MDA was only an on/off display, the word
> monochrome did not refer to this property, only to its' non-polychrome
> property to differentiate it from CGA.
> To further complicate/confound the issue, some video card manufacturers
> found a way to generate a grayscale on the TTL (on/off) monitors. By means
> of a high frequency pulse-width modulation technique wherein the video is
> turned on/off at a rate much too high for the monitor to fully respond to,
> the screen can be made to display the AVERAGE intensity. (Many levels)
> Thanks for giving us something to argue about. ;-)
I didn't give you anything to argue about, but it sure is getting deep,
and I haven't even yet put on my boots. I hope you remembered to put
yours on.
All the best,
Sam Heywood
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