Doesn't look like this went through 6 hours ago, when it was more apropops.
If it did and I'm resending it, please forgive.
Austin wrote:
> I've designed digital imaging systems for 20 years,
> and amongst the equipment I designed was for Imagitex, and was > a digital
halftone pre-press system. The term has always been > halftoning in my
book...and I am curious how the
> term 'dithering' came to 'seemingly' replace it.
I really hate to weigh in here, because it seems to be getting a little out
of hand. But the word "halftone" has been around for centuries in
print-making, most commonly in the engraving trades, particularly in the
mezotint technique ("mezotint" literally translates to "halftone"). It's the
means of achieving many tones between the color of the ink and the color of
the paper, and likewise is the description of that process. Now if you
*really* want to hear some confusing arguments, you should listen to *Art
Critics* discussing what *they* call "halftones"--it's another world! ;-)
Photography did not fully embrace the word "halftone," but comercial
printing did--and remember that engraving was the prime method of printing
magazines and newspapers as late as the 1960's, when high-speed lithography
took over the king-seat.
I frankly don't know when "dithering" appeared on the scene, but it was in
place by 1980 as artists and software engineers pushed out the creative
boundaries of computer graphics. It's a mathmatical approach to giving a
digital image more of the "modeling" that was available in an analog image
on a cathode ray tube, i.e. television. Dithering was one of two ways that
the 128kb Amiga A1000 was able to present photos and modeled graphics on a
CRT in 1984 (it could also pesent--and do--animation, but not of photos). I
could fire mine up and read off the several types of dithering available in
earlier programs--random, ordered, that sort of thing--but it's irrelevant.
"Dithering" is, in fact, another "process" for making a small amount of
colors (RGB, in this case) appear to be many colors, using a finite amount
of ROM and RAM. Once it leaves the realm of the CRT or LCD--to a printer,
let's say--dithering does far less well, because the optics are so much
different. Even so, it's a useful tool as is the halftone process, and any
designer who uses only one idea in exclusive preferrence to the other would
literaly have only half a tool-kit.
So, IMHO, "halftone" and "dithering" are BOTH processes that are used to
arive at an end result--the appearance of modeling and depth on a
2-dimensional surface in lieu of "Continuous Tone" (AHA! didn't mention
*that one*, did I? :-)).
And I hope this puts an end to the bickering--but not necessarily the
discussion.
Best regards--LRA
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