gecko wrote:
> On Fri, 07 Mar 2008 20:03:36 -0500, tacit <tacitr@aol.com> wrote:
>
>
>>
>> Yes, you do need dithering for 256 colors. 256 colors is an
>> extraordinarily limited amount; that's very poor color fidelity
>> indeed. Remember that each shade of the same color counts as a
>> different color.
>
>
> My friend responds:

Why the intermediary in this matter? Is it that you are actually your
"friend" or that your friend doesn't know how to use newsgroups?

> The thing about color --- particularly about fine differences between
> hues of color --- is that it is completely subjective. Film --- and I
> suppose CCDs as well --- is not subjective. Color depends entirely on
> the color temperature of the light. Try taking a color photo with
> fluorescent light to see the difference. The curious thing is that we
> have color memory; if we know what color a thing should be, we will
> see it that way whatever the color temperature of the light. Whites
> look white to us because we know they are white. But white is made to
> appear more white by tinting it most generally with blue, but also
> with yellow and even black. When all the other colors were perfectly
> balanced, Keeping bride's dresses from appearing blue in photos was a
> challenge for me because of the optical whitening added to the fabric.

Not sure how that's relevant, the eye can still discern the fine differences
in only 256 colors whether the hues are cool, warm or just right.

> So, for purposes where actual color is not known or where critical
> rendition of actual color is relatively unimportant, 256 colors will
> suffice. For 4x6 snapshots, 256 is good enough. The toughest challenge
> for film and CCDs is good skin tones. For a large print of a head
> shot, 256 colors are inadequate. Dithering is a poor substitute for
> the infinite modeling provided by film. But I shall need to learn to
> apply the finest dithering the Alps is capable of to be happy with its
> 600 dpi resolution. I thought that my MD-4000 was capable of 1200 dpi,
> but that may be for scanning only.

In my small experience, *any* image with large areas of similar color
suffers from the limitations of 256 colors. I'd venture that that has a more
negative effect than the limitations of 234 dpi. Of course, if you're
looking to output large format, both issues will doom you to some extent.

--
dvus